ok a friend of mine has a 93 Chev p/u with a 5.7 tbi.. he's had it to 3 different shops changed just about everything.. he came over tonight to let me see what it was doing.. what happens is if your doing 80km/h and od is on.. you give it half throttle and it starts to kick and backfire through the tbi.. so I had him stop and give it half throttle from a dead stop.. same thing happens.. I'm assuming tps.. he thinks between that and the egr and map are the only things that haven't been changed..

 

yipe! Through the TBI? geeze. Do you have a stock chip to let it run on to compare? Is the distributor totaly off its mark or something?

 

yes he is running bone stock.. nothing aftermarket..

 

I had the same symptoms on my 92 tbi.
The solution for this was the distributor cap.
It had some deposits build up on the contacts.
Beacuse of this, there was some cross-sparking to other cylinder's contacts.

 

If the tps has a flat spot or spike you may notice a weird shifting pattern at times since it uses that signal to determine what rpm to shift at. As far as the map, it may be bad reading a different altitude/pressure causing the engine to be lean and backfire and pop. The only other thing is it may be and advance problem causing the ignition to be too far advanced at your desired throttle range and igniting the fuel charge up thru the intake. This is controlled by the knock sensor and ECM.