stumbling on acceleration could it be coil pack?
03, turned 100,000 couple weeks ago. I had since early last year when it had 84000. To me it always seemed a little weak on acceleration and hills but it does have 3.07 gears and 31s. But now it is not just steadily slow on acceleration but seems to be stumbling, perhaps misfiring.
I put in new Autolites (standard ones, not platinum) when I purchased it. Checked them couple weeks back (16000 on them) and they look clean, fairly white. No codes, have only had 1 code some time back for throttle position (it happened after washing engine bay), but that I cleared that and it never came back. That was probably a year ago. The oil pressure sensor has also been replaced.
I had fair amount of carbon in throttle body, took it off and cleaned a couple weeks back. Took out injectors last week, cleaned them and put on new o-rings. They were clean on the inside of cone, but carboned on outside.
But as mentioned plugs had no carbon, not dark at all. All plugs consistent color.
It also seems to jerk harshly when letting off gas at times, particularly with A.C. on. Runs not very steady at steady throttle (almost like a vacuum leak), but I suppose this could be A.C. kicking on/off.
Seems like when humidity is higher (also hotter out) it runs worse. Could the coil pack be causing the problems? I have been concentrating on the fuel system, but after running seafoam in gas and Chevron stuff tank before that, plus cleaning throttle body and injectors, can't believe it is still fuel related.
Had an Oldsmobile (Quad 4) which had coil pack issues and replacement fixed it. Oreilly's said perhaps bad O2 sensor causing issues and carbon, but no codes for that. He said it don't always throw a code. He recommended the Seafoam cleaning procedure. I haven't tried that yet.
Tempted to try new coil pack rail, but those are roughly $100 or so, and hate to spend the bucks if that is not the issue.