Need Help-High Idle Condition

[SERPENT]

After installing new fuel system and meth and re-tuning the truck we have a problem with idle. When you're de-acellerating and downshifting up to a stop light and come to a complete stop the idle seems to stick at about 1300 rpm. It eventually drops to 750 rpm but the delay is really annoying and uncomfortable to drive. We have tried adjusting the A/F ratio at idle,both leaning it out and richening the mixture but no fix there.Checked all the vaccuum lines --everything where it should be. Checked the throttle body ( x-metal) doesn't appear to be sticking and is clean. Any suggestions???? Calling Mark at split second this morning for ideas.

 

[TheMoparConnection]

sounds like you either have a vaccum leak or a TPS sensor that is faulty

 

[Yellow venom]

sounds like you either have a vaccum leak or a TPS sensor that is faulty

I agree with TheMoparConnection,I would try TPS first,cheap fix if thats all it is.

 

[SERPENT]

sounds like you either have a vaccum leak or a TPS sensor that is faulty

Thanks-I've seen a number of posts on the TPS sensor.We will look at that next.Sure sux to drive now.

 

[SERPENT]

I agree with TheMoparConnection,I would try TPS first,cheap fix if thats all it is.

Would a faulty TPS sensor throw a code??

 

[BigRed460]

Would a faulty TPS sensor throw a code??

No chances are they wont be a code, but I have noticed that my truck is starting to do that. I wont go into low idle until I am amost stopped.... I just ordered a new TPS so we will see...

 

[SERPENT]

No chances are they wont be a code, but I have noticed that my truck is starting to do that. I wont go into low idle until I am amost stopped.... I just ordered a new TPS so we will see...

Seem to hear about this all of a sudden. We have 17,000 miles on this 04 RC.Does anyone see a trend by year or mileage?

 

[BigRed460]

'05 with 22,000

 

[RedSrt007]

whats your fuel pressure at idle... and are you using boost/vacuum reference..?

 

[01VIPERGTS/ACR]

Sounds like tps to me.I just got off the phone with Mickey,they are on national back order right now.

 

[SERPENT]

Sounds like tps to me.I just got off the phone with Mickey,they are on national back order right now.

Got one located.Delivery this afternoon. Will let you know.

 

[SERPENT]

whats your fuel pressure at idle... and are you using boost/vacuum reference..?

Fuel Pressure is stock 43-46 ? psi with vac off . Rising rate reg 1:1 per psi .

 

[RedSrt007]

Fuel Pressure is stock 43-46 ? psi with vac off . Rising rate reg 1:1 per psi .

seems low...I would run it at 50 vac off. Right now your probably about 40 idle...

not saying it will fix your problem, but youll be amazed what fuel pattern out of injectors can do.

-Red

 

[SERPENT]

seems low...I would run it at 50 vac off. Right now your probably about 40 idle...

not saying it will fix your problem, but youll be amazed what fuel pattern out of injectors can do.

-Red

Thanks-Always love the response you get from the forum.Got the TPS coming this afternoon. We'll try that and then adjust fuel pressure at idle. I'll let you know the outcome. Thanks again.

 

[SERPENT]

seems low...I would run it at 50 vac off. Right now your probably about 40 idle...

not saying it will fix your problem, but youll be amazed what fuel pattern out of injectors can do.

-Red

Got the tps installed.STILL idles at 1300 rpm with slow degradation to 750 at full stop. Next step is proably a new idle air controller. We are going to try your suggestion next(up fuel pressure to 50 psi at idle). Hesitant to do so cause that means total re-map.