305 MAP TPI

idle up and down and all over, then stall, runs great at 1500 rpm and higher, smooth and excellent, but POOR idle.

doest do it as bad with the connector unplugged for the timing, but still surges up and down, but usually doesnt stall. The timing seems to stay put pretty well as its doing it, watching with a timing light.

vacuum guage reads 18-20 inches, up and down following the idle speed.

possible bad egr??

throws a 43 code, but hey...so do all of them....

 

my check engine light has come on for a few dif things and stil does, dunno what for sure exactly., but when mine idled all over and stalled at idle, even in N, i just added a can of that RESTORE..
and it hasnt stalled out since..worth a try

 

Could it be your knock sensor? do you have 5 volts at knock sensor terminal?
have you done anything that might have shorted or ground wires from knock sensor?

 

MeanYellowZ
It's the TPI relays, there are 2 on the firewall drivers side.
Don't replace the TPI unit $$$ Try the relays first.

 

Try your IAC valve under the throttle body. IAC= Idle Air Control. My car did the same thing and thats how I fixed it.
Hope this helps!

 

Thats exactly what my car did a few years ago and all I did was replace the spark plugs and its ran great since.

 

I just had that problem with my 350 TPI. I changed the IAC and it smoothed out my idle as well as made it start better.

 

I would suggest making sure your timing is set at stock. My engine used to do that same thing because i had the timing adv. 13*, A leaking egr solenoid, and a fan switch grounding out on my header. I set my timing back up to 10*(6* is stock for mine) and it still idles a little bad but never dies anymore.