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Erratic engine speed 400 1993

My 1.8 litre 440 (B18U single point injection) seems to have an uncontrollable engine speed. Not only at idle, it is also erratic with throttle partly open which makes driving very difficult and sometimes dangerous. Idle speed can be anywhere up to 4000rpm. No funny noises, black smoke, overheating or other obvious signs of bad stuff.

Searching through the archives, I see many cases of "bad idle" where anything from vacuum leaks, throttle position sensor, sticky throttle to idle control valve are suggested as culprits, but I am not sure which of these could also cause erratic rpm throughout the driving range.

Can anyone help me?

I had noticed a few months back that the revs sometimes oscillated (maybe +/- 200 rpm?) at idle, but it was nowhere near as bad as this.

Any suggestions much appreciated.

Caz






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New Erratic engine speed [400][1993]
posted by  someone claiming to be Caz  on Mon Dec 15 01:29 CST 2003 >


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