[91NissanTruckOwner]

hi

okay so here's the deal, my truck when warmed up idles between 1100 and 850 rpm. typically it is a steady idle at 1050rpm. the weird thing is that when i shut off the engine for a little bit after it's warmed up, then start it up, it idles normally (750 rpm i think.) it will continue idling normally until i rev the truck up to go somewhere, then stop at a red light or something, it idles high again.

another thing, if im in a scenario where I need 3000rpm or more for more than a few minutes (such as going 70mph,) when I'm done the engine will idle at around 1500 rpm for a little while then after about 10 minutes it will go back to idling semi-normal (still idles at like 1050rpm though, unless i turn the engine off for a few minutes, as previously stated.) also during the period when it wants to idle at 1500 rpm, I also notice the engine drops revs a lot slower than usual (e.g. at 3000 rpm i change gears, i can change the gear faster than the rev falls, and the engine is kinda jerked into the rpm range for the next gear, usually around 2000 or so, as opposed to a smooth transition when the engine's revs are falling normally.)

any ideas? thanks

engine has 226000+ miles

 

[noidea]

Perhaps you need to adjust your timing. There should be a label on the inside of your vehicle's bonnet indicating the manufacturer's specs for BTDC, ATDC (Before/After Top Dead Center) and at what rpm.

This vid shows how to adjust ignition timing.
YouTube - How To Guide: Adjusting Ignition Timing

Good luck.

 

[zanegrey]

check the codes and clean and service throttle cable and tbi linkage..

 

[mknight759]

i pressure washed my engine after i purchased the truck and it did the same thing for about a week then poof problem gone and not been back been over a month now

 

[94_nismo_freak]

i had that same prob i wood go for bout a 1/2hr drive at 75-80 at bout 3000r's and then i got off the freeway and would ilde high i wood revit up to bout 4000r's and it wood go down and stay there i then started to changed sensors and after i changed the 02 sensor it stopped completly

 

[SPEEDO]

high idle can also be caused by the thermo element (wax kit) located on the throttle body

 

[94_nismo_freak]

what do you mean by (wax it) lube or clean or what and thermo element? witch one is that on the 240 intake is that on the back of the intake or the one on the side close to the head?

 

[SPEEDO]

thermo element & wax kit = same thing
it acts like a choke, have you checked the throttle position sensor? what throttle body are you using??

 

[91NissanTruckOwner]

Hi,

I've talked to a mechanic, he says it could be the IACV or the AAC Valve?

Opinions?