I have a 2001 GMC Sonoma (same as a chevy s10) with the 2.2L 4 cylinder and a 5 speed manual trans. that at times acts like it wants to stall. 60,000 Miles on odometer. FlexFuel vehicle, but only use gas.
The normal behavior is: foot off gas, clutch in, the tach will drop to
1100 rpm, hold for 2 sec then drop to 900 rpm and stay there. With the AC on, tach will drop to 1100 and stay.The problem behavior: foot off gas, clutch in, tach will drop to 600 rpm, engine shutters like its giong to stall, then rpms climb to 800 and stay. When I blip the throttle this repeates, rpms drop, engine shutters and then recovers. If I turn the AC on while its acting up, RPMs climb to about 1050 and stay, but the engine still hesitates untill I get the rpms up to about 1500, then its got lots of power.
Very intermittent problem. First time, lets say 6 months ago after leaving a gas station, Second time about
3 weeks ago trying to leaving work, Third time today as I pulled in the driveway from work. So its a mix of engine warm and cold. First time it cleared up before I got home from gas station, second time it cleared up after about 5 minutes so I could leave work, third time I pulled into garage and turned it off, but I'm betting it will get me to work in the morning.Truck sees a 30 minute drive to and from work each day, and the hauling of stuff on the weekends. I don't know if it has set an error code, because the service engine soon light has been on for 6 years, and since it still ran great and I lacked free time, I never took it in. And the Smog Pump (air injection pump) is disconected(unpluged) because it caused a parasitec drain that would kill the battery after a few hours.
I know there are some smart people that frequent here because I have been a lurking here for a few years. Any ideas would be appreciated.