5.0 surging question

[mysicman]

A buddy of mine has an 88 GT. Hoping you guys might be able to help trouble shoot. I'm thinking his next step will be to switch to mass air but I'll let those of you who are more knowledgeable make your suggestions. See below for emails:

"Put car in gear after she(respectfully), warms up surges continuously. New air idler, TPs sensor, ignition module, reprogramed computer, checked everywhere for vacum leaks, EGR tested,putting new plugs, wires, distributor, rotor pin, etc...

Speed density! 1988.
I added cold air BK intake, set bolt on short headers.
Seems like it happened after that, now you mentioned it"

Any help appreciated
Thanks in advance
Mike

 

[cotchnobra]

ok there is a part that is called an idle air control adjuster you can get for $60 at late model resto. these are what ford used when a car came in under warranty and had surging idle (idle roll) they go inbetween the iac vavle and the intake. I've seen these fix the problem quite a few times. there is also a gasket with smaller holes for the iac valve but I suggest the first one as u can adjust it with set screws. also you need to set the idle correctly as below
Clear the computer's idle memory by disconnecting the battery for 20+ minutes.

-Disconnect the Idle Air Bypass solenoid
-Reconnect battery
-Start engine and set idle speed to desired RPM with idle screw on throttle body
-Turn off engine and reconnect the air bypass solenoid
-Set TPS voltage between 0.90 - 0.95 volts with a digital volt meter
-Start engine and let it idle for 2 minutes with no accessories on.
-Turn off engine for two minutes
-Start engine again and run for 2 minutes with every accessory turned on.
-Turn engine off again.

were it says to set the voltage between 0.90-0.95 from experience setting the voltage to 0.98 is the best
as for idle rpm you will probably want it to be somewhere around 700-800 rpm

 

[mysicman]

Thanks, I'll pass that on. I know he replaced the "idle air" but I don't know if he adjusted.

Cheers
Mike