1995 Olds Cutlass supreme

[smibgal]

Have what they call a "throw away" Cutlass that started running rough. Long story short the car will now start and idle when you step on the gas it will rev to 2000/2500 rpms then start backfiring and sputtering. I have replaced the fuel pump, fuel filter, EGR valve, map sensor, spark plugs, coil pack, pressure regulator, manifold gaskets, have checked and cleaned the catalytic converter, and checked the relay fuse. Problem is the car has no power, Can't get it to go. Any ideas what the problem is or what else I can do. Please and thank you for any suggestions.

[carriedi]

You have replaced a lot of parts. Money you could have spent to have a shop scan and give you some suggestions on what to do. Backfiring is usually a sign of running too lean. A scan of the data stream would show what your fuel trims are and maybe help figure out what is going on. It's possible that your ignition module might not be firing all the coils correctly so unburned fuel is going into the hot exhaust and being ignited by the cylinders that are firing. Could be that your timing chain is bad. could be a bad mass air flow sensor. could be a bad O2 sensor... and on and on...

with most of the vehicles built after the eighties, you really need a scanner to see what the computer is doing. Even with a scanner it is difficult to figure out what's going on on some cars. Without a scanner you are shooting in the dark. And it could get expensive doing it that way.

use a scanner and see what your fuel trims look like at idle and what happens to them when you try to accelerate. high numbers on the fuel trims means that the computer is adding fuel and low numbers means that it is taking fuel away from what the computer is programmed to believe is normal.

[mgarner9600]

Check spark plug wires are going to the correct spark plugs.... all of your problems sound like the firing order isn't correct. Check even if you are sure your sure! Good Luck

[gotolds]

Ok so i had similar problem on my 95 vert. 3.4 liter. Two strong suggestions: 1. Vacuum leak in particular id say check this nasty dirty greasy hose thats between bottom of motor and firewall for condition holes etc. Or disconnect/bad connect 1 or both sides. Common problem n makes car run like yours. Second vacuum check is hoses up top or first cuz ez but each caused me probs at one time. 2. Crossed or burnt plug wire or wires. Make sure wires are all good and separated with no place that two old ones just sort of burned into eachother over time. Oh yeah and the fuel pump it can be tested at the engine end and is supposed to put out very high and specific pressure. Mine went. Its a quick check with a reader.

[Guest]

had similar problem in a 1991 3.1ltr cutlass--after replacing spark plugs/wires, ignition module and all 3 coils, turned out to be the IAC [and replaced throttle position sensor as well].