97 escort idle problem

[calla1231]

97 escort lx wagon, manual, 173,000 miles
When I stop at a red light or stop sign, it takes 10-15 seconds for the idle to drop down to where it should be, and when I push clutch in to shift gears it doesn't drop down, it stays where it is. No codes are coming up. Ideas? I'm thinking IAC

[GTP Dad]

Good thought!

[P_A_B]

thats a good place to start!

[calla1231]

I tested the IAC and it tested fine. Could it still be that?

[GTP Dad]

Possibly, remove and clean the throttle body and the port where the IAC connects. They can get plugged with carbon and cause idling issues just like a bad IAC.

[denisond3]

If its not the IAC, it could be a vacuum leak that comes and goes. Have a look at the condition of the hose from the PCV valve up to the rubber elbow on top of the throttle body. This 'elbow' eventually rots from carrying so much oily hot vapor. Too bad no one sells just a new elbow - you have to either buy the entire PCV tube and elbow from the dealer, or jury rig a rubber hose to connect the PCV to the throttle body. Myself, I jury rig.

Maybe another possibility: The Throttle Position Sensor (TPS) is how the computer knows you have taken your foot off the gas and it needs to be controlling the rpm. If the TPS is dirty/worn and isnt sending the 'throttle closed' signal, I can imagine the computer wouldnt know to move the IAC valve.

[calla1231]

Got a new IAC, it's still doing the same thing. The elbow and hose all look good. The TPS tested fine.

[electro452]

Originally Posted by calla1231

Got a new IAC, it's still doing the same thing. The elbow and hose all look good. The TPS tested fine.

Mine is doing basically the same thing...it comes and goes.

I replaced my IAC with no change.

I was getting a code saying P1101 which indicates a throttle body or mass flow issue. I cleaned the throttle body out and the Mass air sensor...it seemed to work for a week or so now it's back to high idle intermittently ( 1000 rpm) when I stop.

If you find your issue please post....

[GTP Dad]

Did you remove and clean the throttle body? A build-up of carbon on the throttle body blade can prevent it from closing completely and therefore the engine will idle fast. Not a hard job to do either!

[electro452]

Originally Posted by GTP Dad

Did you remove and clean the throttle body? A build-up of carbon on the throttle body blade can prevent it from closing completely and therefore the engine will idle fast. Not a hard job to do either!

Yes I did. I also cleaned the MAP sensor and cleared the code.

The code hasn't reappeared in few weeks but the idle issue remains.

Maybe I should clean the throttle body again and see if it helps..