escort idle issue

[nickelfritz9]

i have an intermittent idle issue in my 97 ford escort 2.0 sohc auto trans. i never have any issues driving the car going down the road or highway it drives like a dream. here is were it gets interesting because it doesn’t do it all the time most the time it doesn’t but for some odd reason every ones in awhile if i come to a complete stop or even have it in park for a couple minutes it will surge idle up and down rapidly a few hundred rpm like if someone was pressing the gas peddle and letting go repeatedly quickly it will never die will always stay running. ive replaced a few things over the last year trying to figure it out list bellow 142,000 miles it sometimes goes away if i shift it into neutral if im in reverse or drive and im at a complete stop but it will also do it in park sometimes

fuel filter less than 3 months ago wix brand
pcv elbow and valve was sucking shut replaced both
idle air control valve
mass air flow
speed sensor original one failed replaced
cam shaft position sensor poped code for it 3 months ago replaced bwd brand
upstream o2 sensor replaced original senosor at over 100,000 boush
all new exhaust after cat no holes
motor mounts replaced except mount under battery tray
new belt idler and tensioner

Topic

[college man]

The IAC is what mostly controls the idle. Check for vacuum leaks especially around the intake gaskets.

http://www.ericthecarguy.com/faq/solving-automotive-idle-problems

[Frank Heiser]

A couple of times I’ve seen a bad TPS sensor cause that. Could be a vacuum leak as well.

[Author]

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