I have an 86 corvette, and after driving it about a mile, when i try to accelerate, either hard acceleration or just trying to keep up the momentum, the engine seems like it's trying to die, it revs very low and starts backfiring. The car jerks forward and won't pick up speed. I can start it up, rev it and it runs fine. But only after I have started driving do these problems start. I know that it's not the transmission, because I can put it in park, rev it and it does the same thing. The revs drop, and it almost (and sometimes) dies. I was getting the check engine light, got a code 44, replaced the 02 sensor, and now the light doesn't come on. But these problems still persist. What I have replaced: fuel pump, fuel filter, and the 02 sensor. I am getting 39 psi of fuel pressure on the Schrader valve. I don't know what else to do now.

 

Have you checked the condition of your distributor cap? It almost sounds like you are getting arcing inside the cap.

 

Actually , it sounds like a plugged catalytic converter.
You have one option here, you have to take an exhaust system pressure test.
take it to a muffler shop, and ask them to do a pressure test on your exhaust.
Unless you have a heat resistant setup to screw into where the O2 sensor is screwed into.
I think 3psi is the max.

Ok, you have another option, take off the cat, and use coat hangars to separate the cat from the front Y pipe, and to hold up the exhaust so it doesn't drag.
Then drive or rev it and see if it does the same thing.

and don't replace anything else unless you test that part first!!!

Or I get all the parts you take off for free, in which case, go ahead and change anything else you want...........my car is an '86 as well.

 

Thanks for the ideas guys. John, I have only checked the outside of the cap, and there are no cracks in it, etc. I don't think that would cause it to idle and rev perfectly, then just decide to run badly when I go to drive it. coupeguy, My dad was thinking the same thing about the catalytic. I guess that would also explain why it only does it after I have driven it. I did check the pressure coming out of the mufflers, and they are magnaflow, so there should be some pretty good pressure coming out, right? I will try this first, and see how it goes. lol, this should be loud and fun.

Wow, coupeguy, our cars look so much similar, wheels, color, everything.

 

mine's shinier
and I have 1996 collector edition seats............

You have to take the oxygen sensor out and put a gauge there. just feeling at the back of the car doesn't really accomplish anything.
Or, you can remove the cat like you are planning to do.. Just understand it doesn't just slide off. The clamp after all these years has crimped the two pipes together, and you have to use a torch to separate them.
My precats were starting to cause problems around 130,000 miles. I didn't think they would really be a problem since there's not a lot in there to slow down the flow, but it really made a difference when I went to 3 way cats and 90 convertible mufflers.
More power AND quiet inside.
If you don't care about quiet, I have a set of mufflers that will make your car sound a lot better. $150.........

Just to let you know, I just changed my exhaust. I tried cats, no cats, precats, no precats, stock mufflers, loud mufflers, and when I went to my current system, it really likes 1700 RPM to 2400RPM.
It is hard to keep it under 80 on the freeway.
It has a lot more get up and go, or should I say it probably works like it did when new. But since I didn't buy it new, I wouldn't know.
I have done lots of little things to it to make it like a new car................troublefree.
THe next thing I will have to do is lower front ball joints and rear trailing arm bushings in the back. The heat has made the bushings crack, and I will have to change them soon.

 

Just replaced the dist. cap, rotor, coil and plugs yesterday. I cranked it up, and it felt like it was running better at idle, but I couldn't take it for a test drive as I found that the right side valve cover gasket is leaking. Gonna fix that later. I did find a lot of oil on the old plugs. I thought this was due to the car just sitting for awhile. Should it be of any concern?