off idle stumble
11-06-2004, 06:08 PM
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off idle stumble
Any ideas on what could cause a slight stumble/hesitation in the first second of giving it throttle. It's just a momentary flat spot like in the old 4 barrel days. It's had a fresh tune up which did not clear it up.
11-06-2004, 06:36 PM
#2
I think idle air control motor. It could be preventing a smooth transition between idle and openining the throttle. But since your car (needs love) it could be vacuum leaks in some of the air hoses around the top of the motor or new plug wires, etc .
11-07-2004, 10:38 AM
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Yes your is LH Injection so you have a TPS. You can use a volt meter and monitor the signal voltage. Should be .7-9mv at idle, increasing to 4.8V at WOT. Do this test with the engine off, key on. If the TPS is bad then as you slowly move the throttle the voltage will jump around.
The SP are Bosch, not Champion or Autolight, right? Try draining and refilling the fuel tank first.
It has this initial off line stumble when the engine is cold, hot or both?
The SP are Bosch, not Champion or Autolight, right? Try draining and refilling the fuel tank first.
It has this initial off line stumble when the engine is cold, hot or both?
11-07-2004, 10:47 AM
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Originally Posted by svo2r
Any ideas on what could cause a slight stumble/hesitation in the first second of giving it throttle. It's just a momentary flat spot like in the old 4 barrel days. It's had a fresh tune up which did not clear it up.
The LH/EZK TPS is a two-contact device. One contact for idle, one for WOT, open circuit or not; it does not transmit a signal proportional to plate position.
Hesitation can be caused by just about any component of the engine management system, sensors, and/or vacuum leaks. The diag matrix for the LH should be findable by a search. I'd post it now - but I gotta run...
11-07-2004, 10:50 AM
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The stumble could be due to weak mixture. This can be caused by a manifold airleak, as mentioned. It could also be due to a badly aged MAF - how many miles on the car ?
Also, make sure you put the airfilter in the right way up :-) If upside down, it will upset the fuelling.
Also, make sure you put the airfilter in the right way up :-) If upside down, it will upset the fuelling.