Extremely high rpms

[Conster]

My explorer has been acting up for a month or so with what I assumed was a transmission issue. To start with, it's a 92 explorer, AT and cruise control. I'm not sure if the high RPMs are related to the transmission woes or not, so I'm going to start from the beginning.

First thing in the morning, it would go into reverse to get out of the driveway, I'd switch to drive and wait 15 or so seconds for it to decided to actually shift into drive and then proceed up the road to a stopsign. It would seem like it slipped out of great again and take about 5 seconds to shift back into drive to continue. At the redlight to leave the neighborhood, it would mostly stay in gear but go REALLY slow through the intersection. By the time I hit the next redlight, it was generally warmed up enough to not act up any more.

After doing this for a month or so (I like the thing, but it isn't worth the price of a transmission job so was really just waiting for it to die), it decided to start race up the rpms, so I have stopped driving it and want to figure out if it's time to donate it to charity or if it's something reasonably cheap enough to fix.

When I turn the key to the "on" position, the rpm needle immediately pegs up to 4000 rpm (this is with the engine still OFF). If I start it, the engine sounds like the needle is indeed accurate and it is idling at 4000. The gas pedal goes down a little on it's own kinda like when you drive with cruise control on. I found this board and looked to see if there were any other similar posts and saw something about a vacuum modulator valve, but I wasn't sure if my systems matched that being bad or not.

Any advice or tips would be appreciated!

 

[Garretthomas]

to start out after reading it all it kinda sounds like an electrical problem but start by checking your transmission fluid level and is the check engine light on?

 

[Masterd]

Thats scary if it pulling the gas down by itself, like cruise control.

Tranny is most likely done for. Check the fluid color and smell. If its dark brown/black and smells burnt...you can try and do a flush and filter, but its most likely too late.

You brought up the vacuum modulator, but I dont think the VM is going to cause it to slip like yours is.

 

[Alan_V]

My explorer has been acting up for a month or so with what I assumed was a transmission issue. To start with, it's a 92 explorer, AT and cruise control. I'm not sure if the high RPMs are related to the transmission woes or not, so I'm going to start from the beginning.

First thing in the morning, it would go into reverse to get out of the driveway, I'd switch to drive and wait 15 or so seconds for it to decided to actually shift into drive and then proceed up the road to a stopsign. It would seem like it slipped out of great again and take about 5 seconds to shift back into drive to continue. At the redlight to leave the neighborhood, it would mostly stay in gear but go REALLY slow through the intersection. By the time I hit the next redlight, it was generally warmed up enough to not act up any more.

After doing this for a month or so (I like the thing, but it isn't worth the price of a transmission job so was really just waiting for it to die), it decided to start race up the rpms, so I have stopped driving it and want to figure out if it's time to donate it to charity or if it's something reasonably cheap enough to fix.

When I turn the key to the "on" position, the rpm needle immediately pegs up to 4000 rpm (this is with the engine still OFF). If I start it, the engine sounds like the needle is indeed accurate and it is idling at 4000. The gas pedal goes down a little on it's own kinda like when you drive with cruise control on. I found this board and looked to see if there were any other similar posts and saw something about a vacuum modulator valve, but I wasn't sure if my systems matched that being bad or not.

Any advice or tips would be appreciated!

I almost suspect that the delay in shifting is a protective measure. Something in the system doesn't allow it to shift from N to any gear with that much rpm on. It knows is will hurt if it does.

Have you done any repairs recently? If you can feel the throttle moving, you might try bypassing the cruise vacuum to see if there's something in that.

 

[Conster]

Thanks for the advice so far!

I don't think it's a protective measure delaying the gear shift as that was going on BEFORE the high rpm thing started. The delayed gear shift was happening for about a month, with normal rpms. The high rpm is a new thing, I just thought the two problems might be related. The transmission fluid is fine, although it does have a leak so I have to add from time to time (never let it get too low). Color isn't pretty, but it also hasn't been changed in who knows how long. (I've had the explorer for about 3 years.) Doesn't smell burnt.

I haven't driven it for obvious reasons since the rpms shot up to 4000. I had just filled up at a gas station, maybe a couple yards down the road it started doing this so I "idled" my way into a parking lot to wait for the tow truck. When I got it home, we fiddled with the throttle cable, cleaned it a bit and then it acted normal. Drove it around the neighborhood a few times and all was good. Took it on an errand later that day, a mile or less from the house the rpms hit 4000 again. I "idled" my way back home again. Tried fiddling with the throttle cable again but nothing has worked.

I'll see what I can do about bypassing cruise control.

 

[Conster]

I pulled all the fuses that I thought might have something to do with it, and nothing changed. Despite the other transmission issues, I'm leaning towards it having something to do with the throttle. The gas peddle is depressed at all times. Whether the engine is off or on. Like when you are driving down the highway on cruise control. What could be doing this??

 

[Masterd]

Check to see if the throttle cable is binding anywhere.

Take of the black intake tube, and see if the intake butterfly is 100% closed when the pedal is released. It sounds like its not closing all the way.