Im having a wierd idle issue my idle jumps around from 1300-600,back to 1300-700,then it seems to mellow out around 1000rpms and idles around 950 so if i go down the strret and get on it hard it start doing it again its more like a pulse like whomp,whomp,whomp and the starts to mellow down.any ideas?thanks wes

 

Start by cleaning your IAC.

 

I cleaned it already.and it has all new throttlebody/egr spacer.but it was doing that before.

 

You check your TPS voltage lately?

 

what year and what mods?

Edit...its a 92, what mods then...

 

try and set your tps and clean that MAF sensor. A dirty MAF causes 90 % of idle problems on these 5.0's.

 

Suggested to-do list:

- Resetting the base idle
- Setting the TPS voltage (Setting it between .8vdc - 1.0vdc is OK)
- Timing calibration
- Finding possible vacuum leaks.
- DIY KOEO/KOER Self-Tests and Cylinder Balance Test
and if the above link to m-y-5-o-h-.com still doesn’t work, use
- How to run a KOEO, KOER Self-Test codes scan and Cylinder Balance Test, instead. LUK the results.

 

cars is a 88 4 to v8 conversion with a 92 motor,was a speed density car but now mass air,I have a 93 cobra manuel computer,70mm mass air sensor,brand new 70mm throttlebody/egr spacer,ported intake plentuim,24lbs inj,cold air , a adjustable fuel regulater,c4 manuel body with 2500 stall,373 gears,flows and the supercharger is on its way,but i was hoping to get these bugs out first.now adjusting the TPS what voltage and howdo i test it.and its new also came with my throttlebody.