Throttle stuck at strange times

FireflyST

Registered User
So I was driving to work today, and my car begins to accelerate on its own, so I do the only thing I can - brake, pull over, and shut the car off. As it shifts back in to first, the RPMs go way up as if I had the thing floored. The pedal wasn't pulling away so it wasn't cruise. When I was parked safely I revved the engine a couple times, and the problem seemed to go away for the moment. As I turned around to go home, the problem came back. Any idea what this could be? It's incredibly dangerous and there's no way I can drive the car this way. It doesn't seem to happen at any particular speed or throttle position.

The car is a 93 Thunderbird SC.
 
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Is this a normal Thunderbird part or a part that is SC specific? Anyone know?
 
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At the very least, a Thunderbird thing. My '94 V8 did that when it was going out. I think it was the TPS, but I replaced both at the time and forgot which was which now.
 
Why would a bad TPS cause this?:confused:

If the IAC billow has a tear in it, it can act like this, or maybe something is wrong with the solenoid on the IAC and it's sticking open sometimes. Sometimes the housing cracks between the ports and leaks internally too.

If the car seems like it's still running correctly when the RPM's go up high (not acting like a vacuum leak), the problem would have to be the IAC or something wrong with the mechanical parts of the throttle. Any external vacuum leak as big as this sounds would probably cause serious fuel mixture problems. "Internal vacuum leaks" will not affect the fuel mixture, since the MAFS is still metering the flow correctly.
 
just had mine starting to run away and have high idle randomly. come to find out it was the iac, not sure how but somehow the wall between to fwrd and aft chambers was cracked. there was no inpact damage or any other sign pointing to how that could have happened. im sure yours is most likely just a bad iac motor and/or a sticking iac.


and btw, yes i did torque the iac bolts as per spec in the tm
 
just had mine starting to run away and have high idle randomly. come to find out it was the iac, not sure how but somehow the wall between to fwrd and aft chambers was cracked. there was no inpact damage or any other sign pointing to how that could have happened. im sure yours is most likely just a bad iac motor and/or a sticking iac.


and btw, yes i did torque the iac bolts as per spec in the tm

I guess it's a pretty common problem. :confused:

I thought I just broke two of mine. :rolleyes:
 
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