QuestionI have a 1991 Pontiac Grand Am, 2.5 liter, auto trans, 148K miles that was given to me by my sister who told me it ran fine. Come to find out, the problem I'm having was happening to the owner previous to my sister also, but she was not aware of it because of the limited use and short, in-town trips she used it for.
The car doesn't idle well, a bit rough, changing revs, seems to be hunting for the correct idle. I have changed the plugs, plug wires, sprayed the throttle body (TBI with one injector) with cleaner, new air cleaner, changed the oil, flushed and refilled coolant system. I plan on testing sensors and controlled devices, and rebuilding/cleaning the throttle body to correct the rough idle. The car seems to run down the road, city and highway, fine. Until either the engine runs long enough or heats up enough, or both, then it just conks out on me.
First time was coming off the highway on an uphill ramp, it started bogging down before I stopped and then stalled as I stopped, the second time was the same scenario at a level city traffic light. The car was running for about 1/2 hour or less total before each stall, but not constantly, each time there were one or two 15 - 30 min. stops when the car was turned off before the stalling began. After stalling, the engine would start and run fine until it was put in gear, forward or reverse. When put in gear it would stall again immediatly. I tried to get up some rpms in neutral before putting it in drive two or three times, but didn't go too nuts doing that! At least until the last time, when I was stuck in the middle of an intersection, got mad and revved it up to 2-3,000 rpms (? no tach) before slamming it into drive, which actually got the car moving, and whatever the problem was, it corrected itself and got me home, a couple of miles away, during which time it ran normally!
Before this last episode, I was told it was probably the ECM, so I got another one from a junked vehicle (same series #, I put my chip in the "new" ECM), but as I said, that didn't cure the problem. The previous owner that had this problem told me that he used to do just what I did - rev it up and slam it into gear, but I'd like to think I'm not a total idiot, try to keep the tranny and engine from disintegrating, for a while anyway - and so I'd like to fix the problem!
Before I get neck-deep or over my head (more than I already am) in this thing (I have a very bad back and the coil pack, ignition module, crank sensor, etc. is in a very difficult place to reach) can you tell me if you've run into something similar? I'd just like to get an idea of what's the most likely suspect - I want to clean/rebuld the throttle body, test, remove and clean the EGR, as well as check voltages, grounds, vacuum levels, voltage drops, resistances of sensors and controlled devices and all electrical connections in order to get it running well, and inexpensively, I hope. But I really would like to zero in on this stalling problem first, perhaps seeing if all the other work will be worth the trouble and expense.
Any help would be greatly appreciated.
Thanks,
Bill
AnswerHi Bill, try this unplug the converter clutch solenoid, if you don't no wherE it is, it's on the radiator side of the transmission it's has 5 wires going to it, just unpluge it, see will this help on the stalling, on the rough idle replace the maniflold temperature sensor it's to the left of the TBI.
