revving weird and accelerating on its own...

[juju14]

Hey there, I currently came in contact with a 1996 4.0 4wd automatic Ford Explorer. It works just fine and has no leaks. My buddy is going to get rid of it because he said that it did not idle well... I thought I would take a look at it. I changed the Idle Air Control Valve. This did not help at all. What I did notice is that I think it idle's just fine. When the gas is pressed the vehicle almost takes off on its own, it idle's high and pretty much just accelerating on it's own?! When I come to a stop it does some funny revving for 10 seconds drops the battery a bit, then it just idles fine. Almost sounds like it is going to die but doesn't. When I put it into park it rev's from 500 to 2000 over and over. Please help this car is in great shape minus something weird going on. I want to fix this so he doesn't just give it away.

Thanks!!!!

 

[lobo411]

In addition to checking all the usual sensor suspects, I'd try the upper intake manifold gaskets. The rubber gets rigid and they lose their ability to seal over time. I'd imagine a lot of unmetered air would cause the engine to surge as the computer tries to compensate.

 

[rb142]

Agree. I would be looking for an air leak. Someone may also have screwed with the throttle stop trying to "adjust" the idle speed.

 

[coppe]

No cel codes? If you don't see the check engine light on, just open the switch to see if it is working, cause scanning the car will point you to the right direction, so if you don't see the check engine light working, you will most likely have some stored codes in the computer. AutoZone does it for free.

 

[colintrax]

Sounds like the idle air control valve is freaking out. Wouldn't hurt to clean the MAF sensor, they can cause all kinds of weird problems.
My truck did the same thing when the battery broke a cell.

 

[intelisevil]

I want to fix this so he doesn't just give it away.

Thanks!!!!

Don't you mean "I want him to give it to me so I can fix it"?

Good Luck,
Dan