Cold Start Issue

[gyates]

Looking for ideas. My '05 St has 73k miles. I am having issues on "cold start-up", even with the ambient temp at 109. BTW ambient temp does not matter on this issue I am having. I get teh same result whether it is 109 or 70 outside. Bascially when I first start the truck it is idling very low, in 500-600 range. there is no idle "surge", it just idles low immediately. If I hit the throttle gently it will then immediately idle up to 1200-1300 range, then slowly settles at 750 after initial warm-up for the duration of the drive. Idle otherwise is perfect!! Recent repairs include cleaning the MAF sensor, IAC replaced about 6 months ago (Motorcraft unit), and this week the fuel inertia was replaced (had a no start issue adn switch owuld not reset). Fuel filter is also new. Fuel pump replaced about 2 years ago with a Motorcraft unit. No CEL illuminates. I am at a loss on this one!! I am not a mechanic but I am not afraid to do minor repairs like replacing the IAC or cleaning the MAF (already done). ANy ideas apprecaited!!

 

[Ed Fenwick]

Is it possible that the throttle cable may be sticking?

 

[swshawaii]

Throttle body serviced?

 

[gyates]

Thanks for suggestions so far. To hawaii, throttle body is clean, but good idea.



I am wondering if it is possible that the fuel pump relay that is in the electrical box under the hood that is failing? Has anyone had a Fuel Pump relay go bad? Symptoms?

 

[EddieS'04]

Has anyone had a Fuel Pump relay go bad? Symptoms?

It has happened. But if the trac does run. I dont suspect the relay. It could be intermitent though.

IAC replaced about 6 months ago (Motorcraft unit),

It can still be sticking. or going bad. Since it is electronic. Here is a link on how to test it.