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idle speed varies too much

3K views 4 replies 2 participants last post by  JOAT 
G
#1 ·
I have a 90 ford TEMPO with 170,000, manual, FWD.

The engine has rough idle. Idle speed varies a lot, from 500 rpm to 1,500 rpm. Sometimes, the engine is dead during idle (rpm is too low). I have to push the gas pedal to keep the engine alive. Whenever the engine idles, the rpm goes up and down, never stays constant.

I had this problem for a long time. It is getting worse recently.
Another problem could be related to it: during cold start, the idle speed goes lower and lower, at last the engine stops. I have to push the gas pedal several times to keep the engine running. When the engine is hot, this problem goes away.

Any idea is highly appreciated. Thank You.
Alex
 
G
#2 ·
I have a similar problem, I think it is the injector thingy inside the injector body,(I forget what it's called) but have done "some" investigation on it, was told that the internal part wears and allows a fuel flow problem, hope this helps.....
 
#5 ·
first ... pull the ECU codes ....
check for stuck EGR and PCV valves ....
then carb clean the idle bypass valve (may be sticking)
and finally check the Alt / battery voltage while its happening .. low voltage = wrong position for the idle bypass valve ( idle stabalizer)
 
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