This is going to be a little tough to diagnose because of my combination. It's a 94 Impala SS LT1 with a 4L60 in a 68 Camaro. The engine does a bad bog when you hit the gas quickly. It almost stalls but then it seems to rev fine. I'm open to suggestions of what to look for. The car obviously does not have cats, but it does have the O2 sensors.

 

Sounds to me like a bad TPS (Throttle Position Sensor). Its almost like ESP for the PCM. It allows the computer to compensate for the extra load it is about to receive. If this reading is off then your PCM has to play catch-up the entire time. First step is to obviously get it scanned. Next step would be to test the TPS to make sure it is functioning correctly. Here is a pic of what it looks like.

 

I pulled the TPS off last night and checked it with a multimeter. I was able to test the resistance across 2 of the terminals. When the throttle is closed, it was reading around 4.98 ohms(I forget which scale I had it on). At WOT it would read around .72 ohms. But when it went from closed to open it would actually jump up above 5 before it started to go down. So that makes me think it's bad and I'll get a new one tonight. It's probably telling the computer that the throttle just slammed shut when it really is now open. I'll post back the results.

 

Hopefully that does it for you. It sounds like you have a bad spot in the TPS. Good Luck...

 

Well, I put in a new TPS tonight and it helped, but there is still a bit of a bog when you hit the gas. If you floor it completely, it will stumble and backfire. I know I've got a header leak on the left side and I noticed tonight that one of the injectors is different than the others on that side as well. My O2 readings were jumping up and down from 50 to 900 on the left side. The block learns were also high on that side. So it's not worth trying to troubleshoot further until my new headers arrive and I can fix the exhaust leak. But it's too cold in the garage to worry about it for now. I'll post back when I get the leak fixed.

 

yep, exhaust leaks will do it as well. Once you do the headers, then I would worry about it. Good Luck....