QuestionI have a 1994 Chevy 1500 Z71 (4x4) pickup, 350 V8, manual transmission, with a hesitation problem.
I've recently replaced the clutch assy. (due to excessive wear), as well as the EGR valve (with the proper orifice washer), the EGR solenoid, & MAP sensor (due to retrieved error codes). Also, new cap, rotor, and plugs.
The vehicle idles just fine, but under load, it hesitates and "bucks like a bronc" (surge/letoff/surge/letoff) between 1500 and 2300 RPM under normal accelleration and cruising (almost as if it's missing or bogging) in any gear. If I floor it, it "bogs" for a moment and then takes off, but I hate driving like this for obvious reasons.
I don't know if it's related, but the most recent development was last night, after my 5 mi. daily commute, I pulled into my driveway and smelled something - not "burning" but "hot". I popped the hood and both exhaust manifolds were glowing. It was more obvious then after sundown, but I also observed it this morning in the parking lot at work after the same distance trip after sunup.
Thanks in advance for any advice.
Tim
AnswerHi Tim,
I would first check the fuel pressure and make sure it is up to spec, but if it runs ok wide open, it probably is not a fuel supply problem. I do like to know the pressure is there though.
Next would be run the codes, but in the absence of codes, you could still have sensor problems, causing too rich a mixture.
Throttle position sensor comes to mind first, followed by mass airflow sensor, O2 sensor, and temperature sensor.
Good discussion here on the MAF, even though it is a Ford topic, they act the same.
http://www.fordscorpio.co.uk/cleanmaf.htm
Check this discussion for temp sensor info, and a spec chart.
http://www.chevytalk.org/threads/showthreaded.php?Cat=0&Number=1366279
Van
