6th May 2005, 17:27
I had a similar problem recently (my Olds has 150,000 miles and is driven in the country) and the mechanic replaced the map sensor and wiring harness. It runs fine now, but the "check engine soon" light comes on after around 5-10 minutes of driving, which I'm pretty sure has to do with the electronics again, not any other system because the car still runs like it did before it started dying at stoplights. A couple weeks before this latest problem, the gas gage started displaying wrong information and I haven't gotten that fixed yet (I just keep track of mileage and refill every couple hundred miles). Besides those two, I've only had a cracked hose which leaked coolant and a bad fuel filter leaking oil, both very cheap fixes. These latest electronic malfunctions are a a little pricier though ($300) and I'm really hoping they don't lead to worse things!!
4th Jul 2005, 16:06
In regards to your trouble with the 1990 Cutlass Supreme, It may not be an engine or even engine management problem. I have seen early 90's GM vehicles (fwd 4&6 cyl.) that have had faulty switches for the lock up converter, causing them to stay locked as you decelerate, usually during high speed (highway) or areas where moderate speeds are held for longer periods of time. To test this is quite simple. Locate the switch (mounted on the trans. housing) and unplug. Drive the vehicle as normal and you will note that your problem may be gone. It will be fixed right away or this is not your particular problem. If not, clean the contacts on your switch and wiring harness and reattach (after applying some dielectric grease of course). If this does cure your troubles, leave it unplugged. Cost of repair is sometimes worth more than the vehicle itself, and at worst your car will rev a little higher at cruising speed.
25th Aug 2005, 21:43
I read the problem you had with your 1990 Oldsmobile Cutlass Supreme, due to the fact I was searching for the answer myself, before I saw your exact problem. I talked to a few mechanics until one told me the answer over the phone. Solution: common, after a new battery is installed the brain/main computer must reprogram itself, but driving it around won't solve this in this case. Instead, put your emergency brake on, and let your 1990 Oldsmobile Cutlass Supreme idle in gear (I used Drive) for about 20 minutes until your fan comes on; if it doesn't come on within 20 minutes turn your air-conditioner on. This solved the problem of revving up by itself and stalling at stop lights/signs. I doubted this until I tried it. It sounded far fetched to me but it worked.
21st Feb 2005, 08:16
If you still have not found the trouble try looking at the throttle position sensor.