well awhile ago, my 2.8 in one of my Camaros decided to be umm.....weird. It feels like it is cuttin out between 200 and 300 RPMs. It has a new fuel filter, plugs, wires, newer cap and rotor and a new O2 sensor. Since I am going to school for automotive tech, we hooked it up to a scanner but nothing was reading wrong or bad or ANYTHING. My professors couldn't figure it out either. It starts up pretty easily, nothin different then before but it just seems to act really weird. Another thing is after it warms up, it won't idle or it'll die like below 2000 RPMs if I can remember. Any help?? I really don't have a lot of money to drop another motor into it cause I'm building a 454 hi pro to go in it

 

A little more info helps when posting, year and fuel delivery type. If I had to make a guess I would pull the EGR valve and see if it is carboned up. I have seen them so bad there are literally chunks that will break off the pintle. How does it run over 300 rpm? Any big change in gas mileage?

 

oh derr sorry. Its a 1988 2.8 MPFI. It runs better over 3000 RPMs but it still feels like it has a miss in it. My gas mileage wasn't getting any worse/better that I could tell. I usually had to fill it up every week (every 6-7 days). Could it possibly be one of the injector could be FUBARed or one of the plugs coulda come off the top of an injector? My friend had a 1991 Subaru Legacy and he said one of his connectors popped off and it did the same thing. I have narrowed it down to a fuel problem because I also remembered I put a new module in the disty. I also rebuild the disty not too long ago too.

 

Sometimes things like this can be tough to troubleshoot. I usually start with inspection of the plugs, that can be of great help. If you find one that looks different from the rest that narrows it down to a cylinder. Then you can suspect a wire, the plug itself or anything associated. You say it idles rough, try a drop down test. Also, a vacuum guage can be of help when troubleshooting. Could be a dirty injector, try a can of fuel treatment. The only reason I mentioned EGR is that it tends to act up the worst at idle. Usually EGR will throw an O2 sensor code if left running that way. Does it idle better when cold and running in open loop? Don't overlook a vacuum leak somewhere you can't see. Possibly you have an intake manifold leak. LOL, these types of problems can take some time to narrow down.

 

well the ECU isn't putting any codes out unfortunatly. It seems to idle just the same but when you've been driving it and it warms up, thats when it really starts to act up. I added a bottle of Lucas Injector Cleaner into the tank and I let it run for about 20 minutes and no change at all. If it was a vacuum leak, wouldn't it act up more then this? shouldn't it have more problems starting up and running? If I have time, I'll see about pulling the plugs on it tomorrow and seeing if there is any difference in the cylinders.

 

I also remember that it likes to backfire really badly too. I also messed with the timing a bit the day it took a crap on me (like a couple hours before) but I had my timing light hooked up and it was at about 10 degrees BTDC. I disconnected the tan/black wire on the firewall like you're supposed to and I reconnected it when I was done. I hope this helps any more.