[94mustang94]

Here are a list of my mods:

Modifications include:Block bored .030 over to 306 cu in.,DSS Forged Pistons,AFR 165 Aluminum Heads 58cc,Comp cams Roller Rockers,Comp cams Camshaft,Ford Racing Crankshaft,Canton 9 qt Oil pan with pickup,High flow Oil pump,30# Ford Racing Fuel Injectors,255 lph Walbro Fuel pump,Aeromotive adjustable Fuel Pressure Regulator,Ported Cobra Upper and Lower Intake Manifold,Ford Racing Shortie Headers,MAC Cat less Prochamber Pipe (stock hpipe installed for emissions),MAC Cat back Exhaust with 2 inch Chrome Tailpipes,76mm C&L MAF housing with inlet tube and K&N Filter,70mm Throttle Body,MSD Ignition with MSD coil and cap & rotor,PA Performance 185amp Alternator,Under drive Pulley Kit and new harmonic balancer,High flow Water pump,9mm Ford Racing sparkplug wires, Rebuilt T-5 Transmission,SPEC stage 2 Clutch,Cross drilled Front rotors with Hawk pads,New rear rotors and pads,Ford Racing Strut tower brace,New OEM radiator,1997 Mustang GT 17in Wheels with 245/45R17 tires like new,Pro 5.0 ShifterSteeda clutch cable

Now for my problem. I am having a problem with the way the car is idling. It likes to surge up and down really bad even to the point of cutting off. I clean the MAF and the throttle body really good. It makes the car hard to drive. Whats else could it be?

[86er]

iac, vacuum leak, bad o2's

[Nice 5.0]

Check for malfunction codes. If there are any codes this will give you a direction to look in. I would also check your IAC motor and for vacuum leaks as stated above.

[TKOTLARZ]

no, go buy a new iac and new tps and problem sovled...as of right now after u start it and drive down the road the idle is pretty well, atleast not surging and stalling like it would wen u start..i had the same problem and replaced those..the car starts right up and idles perfect right away trust me

[gotn20]

I had a similar problem on my old ghetto set up where a friend gave me a b cam and I had a set of world jr heads on my car, Every body said it was because I had a b cam on a speed density car but I replaced my iac after cleaning it like 50 times and my car idled perfect.

[nolife]

There are quite a few posts around on how to deal with idle hunting/surging. I'd look at those before you start replacing things.
Try some searches or a checklist like this one from another forum (there was one here but I can't find it now)

Help me create the "Surging Idle Checklist" - Mustang Forums at StangNet

My last idle hunting was resolved by lowering my fuel pressure a little. Really depends on your injector size and tune for that though.

[C MY 4D]

What is your TPS set at? Do you have an IAC spacer plate? There also comes a time where the IAC can not supply enough air into the motor at idle. The last car that I built a small <1/8 hole drilled into the throttle body blade cured the issue.

[TKOTLARZ]

Originally Posted by C MY 4D What is your TPS set at? Do you have an IAC spacer plate? There also comes a time where the IAC can not supply enough air into the motor at idle. The last car that I built a small <1/8 hole drilled into the throttle body blade cured the issue.

thats a ghetto rig job

[C MY 4D]

Originally Posted by TKOTLARZ thats a ghetto rig job

Its not uncommon to do this there are many cars that come like that from the factory. The actual fix is the IAC spacer..... the throttle blade couldn't be opened up more because the TPS didn't have anymore adjustment to come back down to idle. Why spend money on a spacer when drilling the throttle plate does the same thing? If you have a better way I would love to hear it.

[nolife]

Originally Posted by TKOTLARZ thats a ghetto rig job

Maybe
The Taurus had an idle problem a few years back and uses a similar IAB design. The Ford TSB fix was a small plate with a "pin" hole to get just enough air around the throttle plate. You can find them in a pick and pull and it will work on the Mustang as well.

[TKOTLARZ]

Originally Posted by C MY 4D Its not uncommon to do this there are many cars that come like that from the factory. The actual fix is the IAC spacer..... the throttle blade couldn't be opened up more because the TPS didn't have anymore adjustment to come back down to idle. Why spend money on a spacer when drilling the throttle plate does the same thing? If you have a better way I would love to hear it.

no jus never heard anything about that before..ive delt with alot of iac problems that were able to be fixed..if uve never heard that and hear it for the first time, it jus doesnt sound like that would be the proper way thats all

[nolife]

Followup to my own post..
If you are interested in the plate I was refering to and don't want to drill a hole in your throttle plate, search for F2PZ-9F939-A. That is the kit to allow minor adjustments of air around your IAB.

[JBIGBOOTSY]

Originally Posted by C MY 4D Its not uncommon to do this there are many cars that come like that from the factory. The actual fix is the IAC spacer..... the throttle blade couldn't be opened up more because the TPS didn't have anymore adjustment to come back down to idle. Why spend money on a spacer when drilling the throttle plate does the same thing? If you have a better way I would love to hear it.

I also have done this, and it fixt idle woes.