I have a 90 Z71 and it runs great, but only when giving it gas or driving. If it just idels it is all over the place. Up and down/ I pulled a TPS code from it and changed it out and sprayed the TBI with cleaner and no change at all! I tryed adjusting the distributor, but I couldn't get it any better. Is this a cam gone bad or what? Please help!!!

 

I have come across a few TBI trucks that have had the same issues that you are describing and what we found was the rod that the throttle plates ride on gets worn out and it makes the truck idle very erratic. They are easy enough to change if you have another truck that you can swap throttle bodies from. Hope this helps...good luck!

 

Take some ether or starting fluid and spray around the intake. Any area that has to do with vacum. Check for a vacum leak first. If the idle changes while you spray a vacum leak, then you found it. But im pretty sure thats your problem.

 

Thanks, I thought it might have to do with the TBI. I checked the bolts on it and I could tighten them up just a bit and I noticed a change. I think I'm going to change the gasket and torque down the bolts and see what happens.
Thanks again!

 

Good deal!!! Glad ya find it!!

 

Truck is still running rough and I pulled a code 43. I changed out the sensor, but no change could the knock sensor be causing the code and rough idle along with the strong fuel smell?
Thanks