i have a 92 camaro and i got a tune port injection in it from an 86 trans am. it is a 350 with a cam and bigger injecters. from day 1 it has given me a lot of problems. you can drive it fine but when it hits wide open throttle it pops through the exhoust and the intake around 3000- 3500 rpm but when it is is park it will rev up just fine at wot . i took it to dyno tune and he could not figure it out. any ideas?

The popping could be a lean condition or it could be an ignition timing problem. I can imagine a degraded spark at high engine speeds due to a bad coil, bad reluctor, module etc. Ignition problems often show their ugly head on a loaded motor that otherwise would run fine.

I can also imagine a vacuum leak causing this. Does this car have a MAF? If so, is the MAF mounted on the throttle body or is there a length of ducting between the MAF and the throttle body? Look in those places for a leak.

Does the car loose power when it pops? Could a bad diverter valve be pumping air into the cat or exhaust manifolds at high engine speeds? If so, it could explain exhaust backfire at least. Also, it probably would lead to a very hot cat / O2 sensor.

Did you experience the backfire on the dyno?

I've heard that too big of a cam will throw off a tune port setup, due to the knock sensor retarding the timing due to the aggressive idle.

ya it lost 150-200 horse on the dyno when it would backfire and it hase headers and no cat but it dose have the 02 sensor on the end of the header i dont know if that would get the 02 sensor to hot?

I do know that the O2 sensor location will have a huge impact on it's reading. On my buds TPI motor, he installed headers and relocated the O2 sensor from just below the exhaust manifold flange to the bung in the header collector. His mixture values were out to lunch - confirmed with a wide band O2 sensor. In his case, he installed a heated O2 sensor and all was well.

I tell you this not because I think it will fix your problem, but it is a possible cause. Can your dyno operator connect a wide band O2 sensor up to your motor to determine where your mixture is?

The other side of things is that the O2 sensor doesn't play a significant role at WOT.

ya he can i will see if will do that

i was told today that my vaules could be set wrong? i dont think it would cause this