So here is the story: The car ('86 IROC 305) was running really rough through teh entire RPM range so I pulled the plugs and ran a compression check as I thought it may be a burnt valve. Every cylinder read 210-220 with most being 210 or so. All the plugs looked good except for #3 which was horribly fuel fouled. I checked the injector harness with a noid light (it indicated okay) and the compression was good. The reading held, losing 5 psi over about 15-20 seconds (leaking through the ring gaps I assume). I checked all of teh injectors with an ohm meter and two or three read 16 and the rest read 15 (#3 read 15). I put a new set of plugs in and the engine cleared up a bunch. Before, it would idle really rough and miss as you accellerated, but it was smooth as butter cruising at 80 MPH or so. The car throws a MAF code, but I have replaced it already. I have also replaced the internals of the dist and the plug wires (albeit about a year ago). Now, the car is much stronger. When you stand on it, it is a bit rough to around 2000 RPM then pulls like brand new until it at shifts 5500 rpm or so I believe. Long story short, I need to get rid of this lower RPM roughness. The car also smelled extremely rich (like burn your eyes rich) before I played with it this weekend, but it seems to be less now. I am at a bit of a loss. I was sure I had a huge problem with a dead hole and was ready to sell the car for what little I could get for it, but now that the car is seemingly checking out okay, I am not so sure I want to part ways. I like driving the car, it handles like a beast and stops on a dime (posi and 4 wheel discs rock!), but I am at a total loss for what the problem could be. Any ideas? I saw something about ALDL software, has anybody tried it? Does it work for things like this or is it more for viewing fuel tables? Which cable will I need to buy or make to make it work with my car? I hope it is teh cheap one! Thanks in advance for any help you are able to offer. Thanks again!!!!!

 

My IROCZ had similar problems, and it was the O2 sensor. If you have access to a scan tool check the cross counts, if it stops increasing it's bad. O2 sensors are fairly cheap (about $20) and they only last 20 - 30k miles, you might just want to replace it. One other idea is to use good fuel injector cleaner like the ones used to pass emmission tests.