So even after the engine is warm, it will idle around 1600-2100rpms. If I turn the idle screw down all the way, the lowest it will go is 1500. Its never done this before in the 3 years ive owned it.

I then decided to see If there were any stored codes, and I got 14, IGF signal from igniter is not input to ECM for 6 consecutive ignitions.

The truck will run great. It just idles high and I cant figure it out.

I was just doing some light city driving up until I noticed the idle wasnt dropped after the engine was warming up.

Any ideas?

 

Throttle body not closing properly?

Idle screw needs adjusting, it's oring compromised?

Luc

 

I think the idle screw is fine. I can adjust it all the way in so the idle lowers, and it only does to 1500rpms.

I think the throttle blade is closing all the way? What do you think?

Truck running


Truck off

 

Looks similar to mine, I'd still be tempted to pull off the intake to and have a gander a the throttle body.

Cold also be the aux air valve stuck open. No coolant going to it or stuck open due to gunk or wear. With a warm engine, place a piece of alluminium tape over the biggest hole inside the tb. Wrap it to the outside, put it all back together and see where she idles then.

 

http://www.ncttora.com/fsm/1990-1995...e/auxiliar.pdf

http://www.ncttora.com/fsm/1990-1995...e/throttle.pdf

 

Did more thinking about your issues. Make sure the cooling system is well burped and pull the EFI fuse for a minute, this will reset he codes. If it cOmes back, then you know it need addressing

Luc

 

Check out your water temperature sensor THW, not to be confused with your water temperature sender which controls your temperature gauge. The THW is probably the single most important sensor that the ECU depends on in order to set engine parameters. Data received from this sensor tells the ECU the current temperature of the engine. From that the ECU controls, ignition timing, fuel, idle speed, etc.
Also if your THW is okay, then you should check the IAC valve operation... a throttle valve with carbon build up on the back side can also cause a high idle condition.
Rule out vacuum leaks as well they can cause high idle also.

 

I guess I need to check out the throttle body.

Also. It idles completely backwards. When cold, idle is at 900. when warm, idle is at 1800

Thanks for the ideas.