High Rev 2000 Constant

[agb2g2]

Hi, I own a RR LWB Classic 1994 4.2 with 74000 miles and last tune up done last weekend, change oil, air filter, clean TB, clean Flow Meter and change plugs, regular gas 89 octane. After reading similar post and try to solve by cleaning the valve at the back of the intake plenum no change at all. Any sugestions on whats the cause how can I know if its the IAC or else? Thanks.

 

[Disco Mike]

Did you clean both sides of the t/body plate as well as the IAC plunger and hole in the manifold? How about the throttle, is it sticking?
When does it rev up, all the time, hot or cold??????????????

 

[agb2g2]

It rev all the time and T/B doesn't stick it looks very clean and yes IAC was cleaned on both sides.

 

[joey]

Try disconnecting the battery, doing a hard reset then connect back up...

Hard reset = connecting positive and Negative terminals together without the battery attached.

 

[agb2g2]

I use the vehicle only on weekends so on weekdays the battery is always disconected on the negative side. I saw cracks on the hose from Air Meter to the T/B can this be the cause?

 

[joey]

Vacuum leaks will cause this, but also after removing the battery it may take 10 minutes of idle time to clear up high idle.

 

[agb2g2]

Will check leaks but after 20 min running idle is still high all the time.

 

[joey]

if after 20 minutes, then check for leaks... I would also make sure that the idle hasn't been manually adjusted via the throttle cable.