First thing first 91 Z28 5.7L TPI Auto Problem 1 code 22 Low voltage at throtle posistion senceor TPS Problem 2 Sometimes will not start, power to everything will not turn over, crank, or try. Reading the codes will allow it to start. Engine will not start, Turn to off, insert paper clip, let the codes flash, turn off, remove clip, and the car starts. Problem 3 After harder driving/traffic/heat problem 2 seems to happen. Often but not everytime the check engine light will come on for a minute. Problem 4 after the driving in problem 3, at a stop the idle will be rough, not irratic or jumping in rpm, just like its shivvering, also the oil pressuse drops and become irratic. Putting it in part or neutral helps and the idle is normal. This only happens after harder/llonger driving. Problem 5 On the highway, between 65-75 and around 2500 rpm there is a lunging feeling at light throttle. Likewise after problem 4 there seems to be a slight hessitation at light throttle. these problems are none exsisting throughout the rpm range in nuetral and park. that is about as copleate as I can think right now, I would appreasiate your ideas and insite. Let me know if i need to clearify anything.