I have a 92 camaro 305 tbi I swapped the motor to a 350 tbi. It's ran great for 2 years with no tune. I worked at n Chevy dealership for 5 years so Im highly certified but I can't seem to fix this problem. Going down the road in tcc lock up (od) you get in the gas and it surges and comes back to life it will do it in any gear only when in closed loop after the motor worms up. Checked o2,tps,map,and distributor all check out fine you let it cool down and drive it and it starts it agsin. It feels almost like a fish bite or a missfire but way worse the motor literally cutrs off for half second then runs like hell. Not loosing any power n my cluster no cel. By the simtoms it should be back firing through the intake but what gets me is it doesn't. All new vaccine lines it does have long tube headers, true duel wxaust flowmaster 10 series single chamber mufflers, that's all the mods besides the pulky system. base timing is 0 degrees tdc in neutral. Any clues ?

 

Did you upgrade injectors to the larger engine?
Did you verify fuel pressure?

 

Fuel pressure was my first thought too...

 

Yes i did verify fuel pressure, no bigger injectors. but I did however get the vehicle to duplicate every time I want it to....its load sensitive slight load on motor and if cutts out does it every time when at operating tempeture. Got it to cut out wile fuel pressure gauge was on it no decrease in fuel pressure

 

Get bigger injectors or get an adjustable fuel pressure regulator, your most likely lean.

 

But its been running fine for a year y now ?

 

One guy can guess fuel injectors. One guy can guess fuel pressure. One guy can theorize that the coolant sensor is goofy. Another will make claims about the MAP sensor. Someone else will ask how old the O2 sensor is, and then we start taking turns at plug wires, distributor cap and rotor, and it'll go on and on and on...

You'll maybe chase your tail for two months until you connect a REAL scan tool, and start looking at the data stream when the engine is acting up.







P.S. Reviewing your post, and correcting all the mis-spelled and outright incorrect words will go a long way towards helping us understand you.

 

The problem is obd 1 is a bitch to read the tech 1 can only do so much its not like the modern obd2 or mdi that tells you everything

 

If you think your computer has a poor data stream, try working with the old Chevette MIN-T system.

So now that you've looked at the data stream with a Tech 1, what is it telling you? Even your OBD-1 system will show rich/lean, open/closed loop, O2 values and cross-counts, fuel trim numbers, knock sensor activity, coolant temp, manifold vacuum, and more.