WoodyBoyd wrote:
2) Have we misidentified the intake temp sensor? The sensor to which I was referring is located on the airbox near the MAF. Ah, now perhaps that's why the tool failed to show that sensor reading wandering off to some default value when disconnected. Thanks, Flash. I wasn't piloting or even co-piloting the scan tool. We didn't bother flushing through all the registers to recognize which entry was way off base.
Small sensor on the side of the air box is a barometric pressure sensor IIRC. Intake air temp sensor is built into the MAP sensor, which is located on top of the intake manifold, towards the back.
WoodyBoyd wrote:
My vehicle starts and idles normally; no bucking, nor missing, nor awful chamber music under the valvecover, nor hesitations--whatsoever. It simply accelerates slowly, spews more soot than normal whilst accelerating, lacks power and tops out at 70 MPH on flat Interstate. Even while in Park or Neutral (engine unloaded), goosing the gas is slow and sootie.
Faulty TURBO or leaky CAC/intercooler hoses?? If so, where or what DTC's would surface? Right now, there are none.
One issue that's sometimes known to occur is the EGR valve getting stuck partially open, so that on acceleration, turbo boost is leaked from the intake to the exhaust through the EGR system. This can cause soot on acceleration. Torn intercooler hose is another possibility, but you'd probably hear a hissing/whistling sound.
WoodyBoyd wrote:
Feels like fuel is being starved or one can't get enough air to satisfy fuel input.
Sounds like it's an air issue if it's running rich enough to blow clouds of soot on acceleration.
WoodyBoyd wrote:
I really do appreciate the varied inputs, they provide great opportunities to think through issues. But if rocker arms (GDE) were broken one might expect a 1st grade speed metal-thrash band raising hell under the hood, difficulty starting and maintaining steady vehicle speed replete with hesistations, misfirings and shuddering; of which there's none.
I think what GDE was referring to is not complete failure, but worn roller bearings on the rockers. This reduces the distance the valves are pushed open.
Here are a couple videos demonstrating worn or seized rocker roller bearings:
https://www.youtube.com/watch?v=8ELktBoWozIhttps://www.youtube.com/watch?v=Kt1Rd7RCIA4