LOST JEEPS :: View topic - Shuddering and bucking ...confused as to why

I pulled the air filter and it looks pretty dirty after 6700 miles. Kind of surprised at all the debris and dirt in there. I will probably drop a new one in and I will look into bleeding the fuel system. I hope I don't have an air leak somewhere because that is going to be a pain to track down.

I have read all about the shudder, but this doesn't feel like the typical tranny shudder. It doesn't only do it between 55-65, but seems to happen no matter what speed I am going. It doesn't happen all the time, but it will do it almost every time when I push hard on the go pedal and then let off. it will buck and bob very similar to a gasser when it is running out of gas. No CEL or anything like that...and it goes away as soon as I give it more go pedal. It will usually disappear about 60 seconds after it starts....very strange. I hope I didn't get a bad tank of fuel that clogged my fuel filter.

This has happened to me as well. First time was about 50 degrees and a drizzly miserable day. After stopping and shutting down for an hour for breakfast, pulled onto the highway and halfway down the entrance ramp at about 2/4 throttle, it fellt like I L.O.S.T. a cylinder, no power, could not make 50 mph with it floored. No fault lamp lit. Limped to the next exit, called Chrysler, and they sent a flatbed wrecker to haul me to the dealer. Dealer checked it out with diag terminal, no faults, it started right up.

Second time, temps about 40 degrees and humid, foggy drizzle. Beat a guy away from a light with hard acceleration to cut over a lane to make a right turn at the next light. It idled fine at the next light, but when I got the green, it was like loosing a cylinder again, no power, bad vibration, no fault lights. I coasted to the side, shut off the motor, waited ten seconds, started it again, and all was well. Any ideas ?? High humidity and rain was a factor, as was acceleration in both of my cases.

The driveshaft is made to be smooth under accel not decel. Together the 2cyl type high compresion engine makes these strange vibs. Also could be a combo of erg closing with all these factors. Now im just making a guess at this most say its the tranny converter.

no-blue-screen

I also had some air in my fuel. I primed and bled a couple of times and she is running much better now. I also replaced the air filter. At 7000 miles, the air filter was pretty dirty...not from oil or soot, but just plain old dirt and debris.

I checked it again the next day after driving 140 miles, and had about the same amount of air. Anyone have the same results when checking? I'll check over the weekend.

I have checked all the above, and it looks good. But still have about the same amount of air, when I purge the system. Anyone else have air like that? Doesn't seem to affect the way it runs.

Author:	no-blue-screen [ Tue Dec 26, 2006 12:26 pm ]
Post subject:	Shuddering and bucking ...confused as to why
Hi all, I have noticed that my CRD shudders and bucks sometimes and this is what I have observed so far: 1) It only seems to happen after brisk accelleration and then letting off the pedal....if I give it more go pedal...then it seems to go away until I let off again. 2) It seems to happen more often when it is raining outside. It doesn't happen all the time...just once in a while and only lasts for a min or so...but the car feels like it is going to stall when this happens...it isn't the normal trans shudder...it is pretty violent...almost seems like the engine is bogging down. It doesn't seem like the tranny...it seems more like a fueling issue....just confused as to where I should start....I will probably take a peek at the air filter this morning....could a wet air filter cause this?

Author:	Joe Romas [ Tue Dec 26, 2006 1:01 pm ]
Post subject:
Where have you been Seriously this is the shudder/stutter problem most of us are having. You have discrbed the situation perfectly We had hoped F37 resolved it but it does not seem to and those that didn't notice it before do now Why, no one seems to know for sure. Could be the torque converter or air in the fue l See this thread. http://www.lostjeeps.com/forum/phpBB3/vie ... hp?t=15783 or do a search on shudder and you'll be reading for days Added. RFCRD suspects the airfilter is getting water logged and causing his turbo seals to leak oil. He's modified a older KJ airbox to help the situation. Also try bleeding your fuel filter and see how much air comes out.

Author:	TDI4BY [ Tue Dec 26, 2006 8:52 pm ]
Post subject:
Mine used to do it bad under just those conditions(not sure if rain makes a diff. though) and I have done NOTHING to it and the problem is totally gone since the ULSD came out. Before ULSD it would do it far less if I ran Bio diesel like B-50 or more. It seems to be a Fuel/EGR problem. I repeat. I did not change anything on mine except fuel. No re-flashes. No fuel filter change. I have never done anything to the CRD except oil changes and fueling it up. I swear it runs better everyday. Does break-in help it too? I don't know but I have 28,000 miles right now. [/b]

Author:	no-blue-screen [ Tue Dec 26, 2006 10:52 pm ]
Post subject:
I pulled the air filter and it looks pretty dirty after 6700 miles. Kind of surprised at all the debris and dirt in there. I will probably drop a new one in and I will look into bleeding the fuel system. I hope I don't have an air leak somewhere because that is going to be a pain to track down. I have read all about the shudder, but this doesn't feel like the typical tranny shudder. It doesn't only do it between 55-65, but seems to happen no matter what speed I am going. It doesn't happen all the time, but it will do it almost every time when I push hard on the go pedal and then let off. it will buck and bob very similar to a gasser when it is running out of gas. No CEL or anything like that...and it goes away as soon as I give it more go pedal. It will usually disappear about 60 seconds after it starts....very strange. I hope I didn't get a bad tank of fuel that clogged my fuel filter.

Author:	Joe Romas [ Wed Dec 27, 2006 8:14 am ]
Post subject:
no-blue-screen wrote: I pulled the air filter and it looks pretty dirty after 6700 miles. Kind of surprised at all the debris and dirt in there. I will probably drop a new one in and I will look into bleeding the fuel system. I hope I don't have an air leak somewhere because that is going to be a pain to track down. I have read all about the shudder, but this doesn't feel like the typical tranny shudder. It doesn't only do it between 55-65, but seems to happen no matter what speed I am going. It doesn't happen all the time, but it will do it almost every time when I push hard on the go pedal and then let off. it will buck and bob very similar to a gasser when it is running out of gas. No CEL or anything like that...and it goes away as soon as I give it more go pedal. It will usually disappear about 60 seconds after it starts....very strange. I hope I didn't get a bad tank of fuel that clogged my fuel filter. Mine gave me the very definet pulsing sensation less then one mile from the dealer the day I bought it My first thought was the salesman just filled it up at BP and got a tank of bad fuel as it indeed felt like it was starving for fuel If you look for it at a steady rate of say 65 mph on a flat road you will get the feeling your being passed by a semi and it's wind is buffiting you around but no semi in sight. (maybe just what your discribing) Not as suttle as what you discribe but longer lasting. Months later I used PS in a tank of fuel labled ULSD and no shudder and it ran noticably better Same for the next tank again with PS. But as soon as I felt good about it with the third tank it was back to normal and maybe worse I should mention that the fuel I use does not bubble or foam at all. In Central Ohio the only BP diesel is rotgut #2 so I avoid BP. I regualarlly use Meijer Premium Diesel. I don't know where it's from but it has always preformed well in my diesels present CRD and past VW's So yes I feel it's partially fuel related but I don't think it's clogging the flow control valve because the effects with these two tanks was instanious I'm retired now and have the time to drive 50 miles round trip to try a tank of B20. My CRD is at 4500 miles. Read the first post only of this thread and you'll see a VM employee has the same problem with his CRD. So from that I think it's a DC problem as opposed to a VM problem but what's new. http://www.lostjeeps.com/forum/phpBB3/vie ... sc&start=0 One person has put a tiny clear "pre filter" before his main filter to watch for air bubbles. Another found the hose clamp going into his pump loose. My hose clamp is not loose and I was able to get a screw driver on it as it points upward in a small area just above the flow control valve. Some have found the banjo fittings loose on the filter. But it could very well be a problem with fluid flow to the TC but I see no pulsing of rpm's on the tac Or could also be the ECM switching the EGR flow control valve on and off at a transition point and getting confused and if that's the case a GOOD patch/flash could cure it.

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Author:	bsmotril [ Tue Jan 02, 2007 6:32 pm ]
Post subject:
This has happened to me as well. First time was about 50 degrees and a drizzly miserable day. After stopping and shutting down for an hour for breakfast, pulled onto the highway and halfway down the entrance ramp at about 2/4 throttle, it fellt like I lost a cylinder, no power, could not make 50 mph with it floored. No fault lamp lit. Limped to the next exit, called Chrysler, and they sent a flatbed wrecker to haul me to the dealer. Dealer checked it out with diag terminal, no faults, it started right up. Second time, temps about 40 degrees and humid, foggy drizzle. Beat a guy away from a light with hard acceleration to cut over a lane to make a right turn at the next light. It idled fine at the next light, but when I got the green, it was like loosing a cylinder again, no power, bad vibration, no fault lights. I coasted to the side, shut off the motor, waited ten seconds, started it again, and all was well. Any ideas ?? High humidity and rain was a factor, as was acceleration in both of my cases.

Author:	RFCRD [ Tue Jan 02, 2007 6:54 pm ]
Post subject:
bsmotril wrote: This has happened to me as well. First time was about 50 degrees and a drizzly miserable day. After stopping and shutting down for an hour for breakfast, pulled onto the highway and halfway down the entrance ramp at about 2/4 throttle, it fellt like I L.O.S.T. a cylinder, no power, could not make 50 mph with it floored. No fault lamp lit. Limped to the next exit, called Chrysler, and they sent a flatbed wrecker to haul me to the dealer. Dealer checked it out with diag terminal, no faults, it started right up. Second time, temps about 40 degrees and humid, foggy drizzle. Beat a guy away from a light with hard acceleration to cut over a lane to make a right turn at the next light. It idled fine at the next light, but when I got the green, it was like loosing a cylinder again, no power, bad vibration, no fault lights. I coasted to the side, shut off the motor, waited ten seconds, started it again, and all was well. Any ideas ?? High humidity and rain was a factor, as was acceleration in both of my cases. Your air filter element got damp/wet from sucking in rain water.

Author:	no-blue-screen [ Tue Jan 02, 2007 7:35 pm ]
Post subject:
I also had some air in my fuel. I primed and bled a couple of times and she is running much better now. I also replaced the air filter. At 7000 miles, the air filter was pretty dirty...not from oil or soot, but just plain old dirt and debris.

Author:	mrwrangler [ Tue Jan 02, 2007 11:34 pm ]
Post subject:	maybe i dont really know but i belive there are three factor
The driveshaft is made to be smooth under accel not decel. Together the 2cyl type high compresion engine makes these strange vibs. Also could be a combo of erg closing with all these factors. Now im just making a guess at this most say its the tranny converter.

Author:	no-blue-screen [ Tue Jan 02, 2007 11:51 pm ]
Post subject:	Re: maybe i dont really know but i belive there are three fa
mrwrangler wrote: The driveshaft is made to be smooth under accel not decel. Together the 2cyl type high compresion engine makes these strange vibs. Also could be a combo of erg closing with all these factors. Now im just making a guess at this most say its the tranny converter. but wait....it can't be my transmission or torque converter cause I am runnin Valvoline ATF+4 fully synthetic with "shudder guard protection" j/k

Author:	kb61751 [ Wed Jan 03, 2007 8:47 am ]
Post subject:
Quote: no-blue-screen I also had some air in my fuel. I primed and bled a couple of times and she is running much better now. I also replaced the air filter. At 7000 miles, the air filter was pretty dirty...not from oil or soot, but just plain old dirt and debris. I also had some air, when I checked the fuel system lastnight. I will check it again this weekend, to see if the air has returned.

Author:	kb61751 [ Thu Jan 04, 2007 8:49 am ]
Post subject:	Again..
I checked it again the next day after driving 140 miles, and had about the same amount of air. Anyone have the same results when checking? I'll check over the weekend.

Author:	Joe Romas [ Sat Jan 06, 2007 6:56 pm ]
Post subject:	Re: Again..
kb61751 wrote: I checked it again the next day after driving 140 miles, and had about the same amount of air. Anyone have the same results when checking? I'll check over the weekend. For starters tighten the 2 clamps and banjo fittings on the fuel filter and then the clamp on the hose on the fuel pressure pump. Mine was pointing up and I was able to check it with a long screw driver. Otherwise it's a pain. Then bleed it, pull the electrical plugs off the filter and push the primer several times and look for fuel leaks there. RFCRD has discovered when he pulled on the fuel heater that i leaks around the plug. He said it "shot out at him" None of mine were loose and I have the same problem and no leaks around the plugs

Author:	kb61751 [ Sat Jan 06, 2007 7:21 pm ]
Post subject:	Air
I have checked all the above, and it looks good. But still have about the same amount of air, when I purge the system. Anyone else have air like that? Doesn't seem to affect the way it runs.

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Author:	RFCRD [ Sat Jan 06, 2007 8:28 pm ]
Post subject:	Re: Air
kb61751 wrote: I have checked all the above, and it looks good. But still have about the same amount of air, when I purge the system. Anyone else have air like that? Doesn't seem to affect the way it runs. Mine pushed some air out too (although through the heater plug) and was running fine. I haven't had any bucking problems since before the F31 recall reflash was done. The only problem I was having is some mild slow/hard starting & rough idle after it was parked for a few days which is highly unusual for mine. This is a classic sign of leakage and loosing prime while parked. When I talked to the CRD tech today, said this is highly probable but not ruling out GP/EGR/FCV starting to fail when I mentioned the soot-clogged manifold sensor. He left me with the impression they all fit together with the heavy soot.

Author:	BioJeep [ Tue Jan 09, 2007 3:03 pm ]
Post subject:
Quote: I have checked all the above, and it looks good. But still have about the same amount of air, when I purge the system. Anyone else have air like that? Doesn't seem to affect the way it runs. I had an air leak appear at ~2200 miles that caused shuddering at high throttle, usually followed by limp and sometimes by the engine dying. Dealer eventually replaced tank module & associated rubber fuel line. Has run fantastic ever since but I still find air whenever I bleed the lines, even after only ~50 miles of driving. Bugs me and may troubleshoot eventually but doesn't seem to affect operation at all. Some air seems at least tolerable if not normal in a fuel system like ours. I suspect that if it was critical, then the design would be different, as an air leak is not only so easily gained but also very difficult to find, but I do wish I knew this as a fact.