Im looking for some answers before i take my car somewhere and pay an arm and a leg to get the problem diagnosed. Mods are listed in the sig... The car does exactly what the topic says, when i get on the gas quickly the car will rev to ~2500, ~3000 RPM and then fall on its face. The tach will go down to ~1500 and the exhaust will backfire with a very noticable loss in power. There is no smoke of any kind coming from the exhaust. I dont have a code scanner so i cant be much more specific than that. Plugs were changed to Bosch Platinums (single tipped) about 6 weeks ago, gapped at .035". The wires are in good shape. What are the likelihoods that i am having an ignition problem? Fuel problem? Bad MAP sensor?
Thanks for any help, Ill be back soon:hail:

 

After more driving tonite i found that the stumbling is happening because of a certain throttle position (~70%) and not at any specific point in the tach. Anything above or at that throttle position is causing the power loss. When i left the car in lower gears i could run the motor all the way up to the redline without any problems or power loss....
Thanks

 

Have you checked the TPS for a flat spot, the voltage increase from idle to WOT should be smooth.

 

I cleaned out the IAC and checked the TPS voltage levels. The voltage level at idle seemed very low, it was below 0.50 V. Mind you, this is a speed density car, so the voltage level should be in the 0.710 V range. I tried to adjust the TPS by loosening the torx screws and adjusting, but i could only get the voltage level up to ~0.520 before i ran out of contact room between the TPS arm and the TB connecting arm. I then adjusted the idle screw to bring the arms into contact until i reached 0.710 V. I turned on the ignition for 15 secs and then started the car. The idle seemed extremely high, ~1500 RPM. I didnt have a chance to take the car out, so i will do that tomorrow and see if any of the driveability issues have been taken care of. Thanks again for the help.
btw, the TPS didnt seem to have any flat spots when adjusting to WOT, and WOT ended up at 4.2 V

 

Well, this morning i went to reset the minimum air value following the tech article. I couldnt get the minimum air idle even close to 400 RPM. The lowest i could get it was 1100 RPM, the throttle body simply wouldnt rotate any farther back towards the idle screw. I reconnected the IAC and pulled the ALDS short and, poof, magic, the car didnt have the hesitation anymore. Idle was at 650 RPM, +- 75 RPM. I drove it around though and it didnt seem to have the tire shredding torque that it used to have. The TPS voltage reading at idle is once again real low after adjusting the minimum air value. TPS idle reading is 0.408 V.
I cant seem to be able to rotate my TPS to change the voltage levels withuot adjusting the idle screw. There are two torx screws and they just dont give enough leeway for me to adjust the TPS. Anyone?

 

well, the loss of power had a real simple explanation. After checking the TPS voltage levels through a full sweep, at WOT i was only getting 3.38 V. The problem: the screw clamp for my air filter was obstructing the throttle body rotation, moved the screw and I am now at 4.3- V at WOT. Took the car out and it moves again. I managed to get TPS idle level up to 0.524 V, so i guess that i will have to do.