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sticky throttle - cable or speed sensor?


beerhunter

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Hi

Thanks again for all your continued help. I took the truck for its test today.

Good news is it's mostly OK (including all the things I've fixed!). It did fail on emissions - high CO (7.3% vs limit of 3.5% at idle) and HC (1755 ppm vs limit of 1200 ppm at idle). I've been reading threads and will crawl over the engine later.

It drove fine on the way to the tester. However, on the way back, the revs insist on sitting at 3000, and only come down when you engage the clutch (so it's under load).

I expect it's a sticky cable, although it's not immediately apparent. My question is, could this be speed sensor related? I ask as someone had deliberately disconnected it - for this reason? I recently replaced the senor because I want and need a working speedo.

If, however, a duff sensor doesn't/won't show these symptoms, it'd be great to know I can disregard it as the villain.

Many thanks
 


Denisefwd93

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Hi

Thanks again for all your continued help. I took the truck for its test today.

Good news is it's mostly OK (including all the things I've fixed!). It did fail on emissions - high CO (7.3% vs limit of 3.5% at idle) and HC (1755 ppm vs limit of 1200 ppm at idle). I've been reading threads and will crawl over the engine later.

It drove fine on the way to the tester. However, on the way back, the revs insist on sitting at 3000, and only come down when you engage the clutch (so it's under load).

I expect it's a sticky cable, although it's not immediately apparent. My question is, could this be speed sensor related? I ask as someone had deliberately disconnected it - for this reason? I recently replaced the senor because I want and need a working speedo.

If, however, a duff sensor doesn't/won't show these symptoms, it'd be great to know I can disregard it as the villain.

Many thanks
Well you may want to do a recap since everyone probably doesn't know what you were doing and what you are working on. I just picked up another truck and has a typical high speed idle. It's usually the IAC.
 

beerhunter

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Thanks. The truck was idling fine (approx 800 rpm at once up to temp). However today it had decided 3000 is more appropriate.

The stuff I have been working on was suspension and steering related, so nothing to do with this issue. Apart from fitting a new speed sensor.
 

rusty ol ranger

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Thanks. The truck was idling fine (approx 800 rpm at once up to temp). However today it had decided 3000 is more appropriate.

The stuff I have been working on was suspension and steering related, so nothing to do with this issue. Apart from fitting a new speed sensor.
Never heard of a tps sticking.

Next time its idleing to the moon pop the hood and try pushing the TB closed by hand. If it doesnt calm down try wacking the IAC with a screwdriver handle.
 

beerhunter

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Thanks. Annoyingly, this issue has gone away without my having done anything to fix it. Hopefully it stays away...
 

rusty ol ranger

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Thanks. Annoyingly, this issue has gone away without my having done anything to fix it. Hopefully it stays away...
Sounds like typical IAC BS
 

wildbill23c

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Floor mat stuck under the accelerator pedal.
 

beerhunter

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No mats in it. I did go all over the footwell for anything that may have poked or somehow got snarled up, but that doesn't seem to be the answer. I'll replace the IAC and keep checking the cable regularly.

Thanks
 

adsm08

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I agree. This sounds like a typical sticking IAC.

If the throttle body or the able were sticking you would notice the pedal not returning.
 

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