GM 2.2L wants to stall

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.

Reply to
wcs94
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Is that supposed to be a 100,000 mile tune up vehicle? If you've never changed the plugs yet I'd throw a set in. Also a new fuel filter is probably due too.

Has the engine light come on?

It could be anything from a vacuum leak to a faulty sensor/plug.

I have access to service bulletins and I didn't see anything related to your problem.

Reply to
CEG

"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."

You've had a check engine light for six years, and now you want to know why it hesitates/doesn't idle correctly? I would say as a first step, run it down to your local auto zone/checker/kragen/murrays and have them read out the OBD-II codes. They will do it for free. Post the codes here when you get them, they are 5 characters long and start with a letter. There is probably more than one, and since the light has been on for six years whatever was wrong six years ago is still broken today and is probably getting worse....

Chris

Reply to
Hal

..."Don't know if it set a code, cause the light has been on for 6 years." LOL ..."The smog pump killed the battery in a couple of hours." LMAO

Reply to
twisted

Get the codes read and let us know.

Reply to
ben91932

Father in law has one of these turkeys. When the alternator went out he sent it to a dealership to have it repaired. Thereafter, the check engine light came on.

Same dealership said it was the oxygen sensors. Replaced them.. Didnt help**

Took it back in and they said the original mechanic had not plugged in the new sensors.

In a few days it recurred.

Then they said it was the computer. Replaced it. A few days later the light came back on.

We got tired of that mess, and drove it for a couple of years.

Finally took it back to the dealership and ****> a competent

Reply to
hls

Funny, I drove a rental 2005 Malibu with a 2.2 Ecotec about 3000 miles a few years ago, and got 34 mpg highway, and high 20's city. Plenty of power for my needs too. Probably get one in my next used car. My first OHC. Hard to find any complaints about it, which is kind of scary. Too much praise for the Ecotec. I'm used to hearing endless whining about problems with GM engines, which saves me thousands when I buy a GM car, then have no real problems with them. I need more complaints like yours to save me money.

--Vic

Reply to
Vic Smith

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