idle problems

[Serge]

need some help my car run good some time at idle it will idle down run rough but not stall i change the fuel pump filter and tps sensor and adjusted the tps sensor at .90 volt and still ones and a will wild start idleing at 500 to 600rpm and then go back up to 1000rpm and run good..
what else can i do. and i just change the IAC still does it

 

[LTmach21]

Does the car have the factory intake?

 

[Mattstang04]

Is the Idle Air Control valve acting up? Test it by getting it to idle bad, disconnect the valve, if there is no change then that may be a problem, if it does change then likely a different issue. If it is the problem let me advise you to replace it with Motorcraft. Some aftermarket companies make IACs that do not play well with these mod motors.

 

[Serge]

Is the Idle Air Control valve acting up? Test it by getting it to idle bad, disconnect the valve, if there is no change then that may be a problem, if it does change then likely a different issue. If it is the problem let me advise you to replace it with Motorcraft. Some aftermarket companies make IACs that do not play well with these mod motors.

thanks for the info it is the IAC i got a new one on order..

 

[nxhappy]

yep ford IAC is a POS. most of the time can be fixed with carb cleaner and a good cleaning.

 

[Serge]

ok now i have no clue i change IAC and still goes to low idle ???? could the mas air flow sensor have affect on idle