1988 300 has an idle problem... When you start up the engine the idle surges between 500-1000 rpm. And before installing a new tps, would hold a warm idle at around 750 i wanna say. And after installing new tps warm idle sits between 500-600. And still has the surging problem, only now it surges so much that it'll stall out. In the mornings I'll have to start the truck 3 or 4 times to get out of the driveway.

New IAC and TPS

Only code I'm getting is 67, which has nothing to do with this

 

I got the same problem with my 87 with a 302, and also no codes!

 

It takes a bit for the computer to adjust to the new iac. It should get better.

 

Iac was installed weeks ago. Should have adjusted by now

 

how dirty is the throttle body? that can cause it.

 

Cleaned throttle body last weekend. That was my first thought

 

There is a certain way that to a needs to be put on. Put the tabs on each side of the blade and turn clock wise.

 

You can back prob and test it to see if it is right I stead of taken it off.

 

Replaced tps again. Old one was faulty. Apparently I don't knowbhow to install this thing. I put another new one on and its still giving me the same code

 

No more tps problems. Still having low idle and surging though. Warm idle is at about 600. Cold is right about 500