so i bought and 86 rx7 2 days later i was on my way to the wrecking yard to look for parts and on while i was on the freeway i noticed that when i would let off on the gas the car would just revv itself to reline and stay there so i pulled over and stopped at a gas station started it up and did the same thing and a bunch of white smoke came out i had to get it home. to me it only made sense that the mass airflow sensor was the problem i replaced it with one thats works i got from a friend and still the same thing. maybe a new pcm?

 

Your problem is not likely electrical, so you can forget about the AFM or ECU being related. Check the throttle linkage, and be sure the cable is not binding up.

 

Definitely throttle related. Check to make sure there isn't a rag in the throttle body. I was smog checking a honda civic that had the same problem, found a rag in the throttle body.

 

interesting well ill check it tomorrow

 

i just checked it right now, and nothing seems to be binding up, what i dont understand is, while i was driving in and it i kept my foot on the gas it would rev they way it should and the rpm would drop to 3k on the highway it was only when i let my foot off the gas that it would jump straight up

 

Yup! That is your ECU. I got that before after rebuilding my engine and the first time I drove it for break in bam! It's one of the those resistors on the ECU opened up. If your gonna replace the resistor just look for a 1/8 watt or 1/4 watt better of 4.2 ohm, since I can't find that value at radio shack I just got my self two 10 ohm resistor and install them in parallel which gives me a 5 ohm resistance, I know it's not perfect but close enough and I got her back and running. If this is too much of a hassle for you, just buy another ecu.

 

thanks mani kinda figured that that had to be it. im just gonna part out the car though things been sitting for 2 years in my back yard