Idle Problems

I have a 2007 X-Runner. 65k on motor with a new T56 Magnum. I'm running a Unichip, exhaust, AFE intake. Sometimes the truck is idling fine, other times it's around 450 to 550rpm. Sometimes it'll go into limp mode as well. I pulled codes P0171 & 174. New MAF, throttle body, and cleaned intake filter. Problem persists. Sometimes while coming to a stop, while in neutral, RPM's fluctuate from 800 to 1500, up and down. When at complete stop, they drop to around 500rpm and if I don't play with the throttle to keep them up near 8-900, limp mode will activate. After I'm rolling truck feels fine with no hiccups. Please help!

 

Look for a vacuum leak

 

I sprayed a bunch of brake cleaner everywhere around motor but never changed/fluctuated idle. I'll try again.

 

Welcome to the T56 club.

Check your couplings for the intake, if you have an old AFe intake.

Do you have a catch can?

How do your pcv hose ends, and other vacuum hoses look?

Any engine bay pictures?

 

Looks like throttle body might be leaking a little bit of Coolant. Could that be the problem?

 

No.

 

PCV hose is a little bent and might not be getting 100% flow

 

The number one culprit of any idle issues is usually the idle positioning sensor. I would start with that and if the original is still in, your lucky it has lasted this long. If you are near a CarQuest, they usually carry OEM Denso and avoid going to the dealer. Good luck.

 

That is the TB on these.

 

Where is the IPS located?

 

Did you read these questions below?

 

Couplings are all new. No catch can.

 

Thank you.

Vacuum hoses. Check the ends of everyone of them. They will be split and hard, with that age, unless you have replaced them.

 

I've never replaced any vacuum hose. I'll check asap.

 

You state that you are throwing both P0171 and P0174, Those are both intake problem codes and you seem to have replaced the parts that could be causing codes. I assume you have a 4.0 V6 because you are throwing codes for both sides of the block (right and left). Think of it as one going in (air intake) into two going out (exhaust) hence the two codes. So your problem is defiantly intake. As many have suggested, you can listen for vacuum leaks (I always find that tough with an engine running) or an intake gasket leak. Try this test https://video.search.yahoo.com/sear...iew&id=7&vid=4b23586c2056df2c86f557c0dd8d1e60 or if you are daring and have the time, do the smoke test. I did this on a 1998 Tacoma 2.4L 4 using a cigar once and it worked for me. Once again, good luck!

 

Smoke it

 

Spray it.

 

Put the old parts back on the truck and see if the problem goes away

 

Listen to Tor when it comes to engine performance modification related issues.

 

Tor, spray what exactly?