Recently I helped my old man put together a 350 TPI to replace his ailing L98 in his '88 GTA. We used hypereutectic flattops, stock rods and crank, LT1 f-body cam, and freshened everything up. Everything was put back together and the engine sounds good and runs fine. But when you take off, it sputters for a second like it has a dead spot in it, then it takes off. Runs well otherwise. This problem didn't exist before, and the TPS and fuel system are good. Throws codes 33 and 34 though we cant find any problems. Anybody have any ideas where to look...? I'm out of ideas!

 

ttt

 

33 & 34 are MAF related. try replacing the MAF burnoff relay and/or troubleshooting the MAF sensor/wiring.

HTH,

 

Could be timing too when i had mine higher it would do somthing simular at low rpm.

 

What did you do to the chip to compensate for the cam change? The computer is probably going nuts trying to figure the cam out and such. just a suggestion....

 

What did you do to the chip to compensate for the cam change? The computer is probably going nuts trying to figure the cam out and such. just a suggestion....

 

What did you do to the chip to compensate for the cam change? The computer is probably going nuts trying to figure the cam out and such. just a suggestion....

 

Eh thats a baby cam. No computer mods needed to get it to run right.. I ran the LT4 hotcam with stock computer.

 

Im having the same type problem I have an 89 GTA with the tpi 350 which i put vortec heads the SDPC intake and a .488 / .498 lift comp cam in. at least thats what i think the lift is don't have the info in front of me. It stumbles right when you hit the gas and dosen't have a lot of powe until it hits 2000 rpm's. I have a chip from PCM for less.

 

Another possibility could be the EGR valve...I have had issues with this on my 350 in my suburban (1994) and the EGR valve was sticky...so I replaced it and the bog went away.

To dhirocz: definitely take care of the MAF related codes first....

 

I would put the stock chip in and see what happens. We ran the stock 89 350 TPI chip on my 383 219 cammed motor and although it wasnt perfect performance, drivability was fine.

 

Back when my 81 Z28 had a computer I had a similar problem after installing a rebuilt carb. A slight adjustment to the throttle position sensor took care of that dead spot between 1800 and 2200 rpm. Could a fuel injected car have a similar tps issue?

 

if the car has a active maf related code it will stay in "limp mode" and not run at peak performance. address the issue the car is telling you is there and then reply.

 

OK, We'll look into the MAF code and possibly the EGR valve. Then we'll report back...