1987 Bronco II Idle issues

[markymarkbandit]

My Bronco will idle fine when I first start it. Once I hit the gas it will not return to the appropriate idle. Any ideas? Thanks

 

[ab_slack]

First make sure the mechanical linkage is good. I've had problems with the linkage sticking so if idle stays elevated it could be that.

The idle is controlled by the computer. Making mechanical adjustments to try and set the idle tend to make perhaps a temporary change but when the computer adjusts you are back to where you were.

It could also be a throttle position sensor or a whole host of things. Best to go thru the KOEO and KOER tests. That will give a check on the throttle position sensor range and a bunch of other sensors for basic faults.

That is where I would start.

 

[markymarkbandit]

Thank you for the response. Turned out my mechanical linkage was sticking. I never thought to check that. Sometimes it's the most simple resolution.

 

[huntersebastian1]

I have an 87 with the 2.9 and I seem to have a similar problem. Ill just be driving along and especially in 3rd gear I can let off the gas and it will stay at about 3000 rpms. Even when i push the clutch in to come to a stop until im basically stopped them it will go back down to where it needs to be. Any ideas?

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[Johnluhot]

I have an 87 with the 2.9 and I seem to have a similar problem. Ill just be driving along and especially in 3rd gear I can let off the gas and it will stay at about 3000 rpms. Even when i push the clutch in to come to a stop until im basically stopped them it will go back down to where it needs to be. Any ideas?

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Will it stay stuck at 3k if you rev it at a standstill? And if rev it in neutral while moving? Or is it only when you just come out of gear?

 

[huntersebastian1]

Both, when im in gear and push in the clutch itll stay at 3k too

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[Johnluhot]

Both, when im in gear and push in the clutch itll stay at 3k too

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You may have already checked this, but vacuum line leaks? Air intake gaskets sealing properly?

You mentioned that it would return to normal idle, how long would that take?