I have A 94 oldsmobile delta 88 with A 3.8 engine. When I go down the road it dies when I let off the gas. Doesn't matter if I am driving straight or on curves. The check engine light comes on intermitently also, and it's died when the light was off. Doesn't seme to matter. Question- EGR valve or throttle position senser. Oh and the idle seems to vary it's speed intermitently, not smoothe. Anybody got any ideas? Best guess would help. I have all the tools I need, but no diagnostic computer, and I have time.

I am far from being a mechanic...but had a car that did that and it was the fuel pump in the gas tank. I'm probably way off...but thought I would throw it in there

Any troubles starting?

ECM

Fuel pump

Possibly crank sensor

More than likely something on the throttle body, TPS, Idle air control, or the throttle body itself. Could be a vacuum leak somewhere as it sounds like the engine is running way too lean when you lift off the gas.

I had issues with one like this once.

I would test the TPS sensor if it is bad, make sure they check the idle air motor....I replaced 5 TPS sensors before I found out that trick..

it's an oldsmobile....push it over a cliff






Next....

And buy a Honda

Could be Oxygen Sensor, fuel pump, a bad valve, perhaps a tune up, Vacuum leak like someone else stated....those 3.8's are a piece of crap. I had a 96 pontiac grandprix 3.8...worst engine and Tranny ever!!!

Anyway, Auto Zone offers a free check engine service. He will plug it into the computer and run a check, then it will come back with a list of possible things it could be.

Although one thing can be another. like if you do a vacuum leak, it could be a bad oxygen sensor....

as far as the fuel pump goes...you should hear a bit of a "hum" after you turn the key, but before you start the actual car. Then you know that's working.

Oxygen sensor might be located near the Throttle body, another reason it could be that...good luck!!!

A '94 GM should have OBD 1 computer system. Under the dash on the driver (left) side you will find the data link connector. If you don't have the diagnostic computer to hook up to then get yourself a paper clip or some sort of small flexable wire. The connector has two rows of pins. On the upper right hand side you will need to connect the farthest two pins with the paper clip or whatever you have. Leave the two pins connected and turn the key to the run position, the check engine light will start to flash. I will flash slowly and then quickly. The slow flashes are the first digit and the quick flashes are the second digit. If you have any trouble codes it will flash each code three times and then after a short break it will repeat the codes. one slow flash followed by two quick flashes means code 12. Once you get all the codes go to AutoZone or some other do it yourself auto parts store and they will tell you what the code corresponse to. You may have a MAP sensor problem or a vacuum leak. Good luck bro.

btw once you have the codes remove the paper clip. This only works on GM vehicles with OBD 1 computer systems. Don't try this on OBD II or any other non GM vehicle. Even if the check engine light doesn't stay on the computer should keep codes in memory, as long as you have not lost battery power.

Thank you all for the help! It's nice to know there are still people willing to help!

So what was it?

I haven't gotten around to working on it yet. I will let you know though. I just hope I have enough patience, or it will get fixed with A hammer.

vacuum leak is the most likely and easiest to fix. If you haven't replaced the suction hoses around the engine, now is the time to do it anyway.