'99 Isuzu rodeo with an idle problem

[Jinx]

Ok I have a good buddy whose son has a 99 rodeo LSE that has an idle issue where it idles at 3000 rpm when it goes in park.

Vehicle has has recently had the Heads done along timing belt water pump etc.

sounds to me like a idle control motor but I am not sure on a Isuzu,

anyone have any thoughts?

thanks in advance!

(mods feel free to move this as needed)

 

[rholbrook]

Throttle Position Sensor possibly. It should be less than $30

 

[Jinx]

Good call. Will it flash a code for that?

i forgot to mention no codes.

 

[thefirstzukman]

Vacuum leak? TPS would give you a dead spot or just die, defiantly run ability issue with check engine light pretty quickly. IAC could cause it, but usually a no idle issue vs a high idle issue. Vacuum leak would defiantly give you a high idle and if it just had heads done it is a good possibility, you would eventually get a engine light from long term fuel trim issue unless it was an extreme leak and then it wouldn't run very well.

 

[bryson]

Does it use a mass air flow (MAF) meter? It's common to have idle issues (and poor running issues) if the intake hose between the MAF and the throttle body is damaged. If the hose (usually made of flexible rubber or similar) is torn or cracked, then the engine is taking in different amounts of air than the MAF is accounting for, which could be causing the issues. If the engine was recently worked on there is a good chance the hose is damaged (they get brittle with age, and removal and re-installation aren't always done gently.) Bad engine mounts can cause the hose to tear as well, since one end of the hose is attached to the MAF, which usually mounted in the air box on the body - If the engine can move more than the hose is designed to allow, the hose becomes the fuse.

A new intake hose for the few vehicles I've encountered with this issue (Land Cruiser, XTerra, forget what else) were <$100 even from the dealer. It's not a terribly uncommon problem.

 

[smartass_kid]

i had a rodeo years ago and the throttle cable started getting stuck. if it's related to acceleration at all, check it out.

 

[Jinx]

Thanks for input. We will start chasing these ideas down.

Please don't hesitate to chime in with ideas...