I need some advise. My 98 F150 4x4 4.6 is having trouble starting when it's cold. Recently when it's been below freezing and the truck has sat overnight. I find that when I go to start it, it will barely run for the first 15 to 30 seconds. Motor is only reving at maybe 300 rpm or so. Then all of a sudden, something must be opening up or starting to work, because the motor revs up to about 2000 rpm and returns to a normal cold engine high idle.

My truck has just shy of 110K on it. Fuel filter was changed about 6 weeks ago. Plugs this past summer.

Any ideas? There are times I wish these dam things still ran simple carburators.

Thanks

 

svt,

Only a guess on my part but I'd check the IAC (idle air control) and the TPS(throttle position sensor).


Good Luck,

Bill

 

svt,

Just found this TSB regarding '98 4.6/5.4 engines: causes rough idle/misfire after cold startup


Make: FORD TRUCK Year: 1998
Service Bulletin Number: 00261 Bulletin Sequence Number: 168 Date of Bulletin: 12/00
NHTSA Item Number: 616826
Component: FUEL:FUEL INJECTION:IDLE SPEED CONTROL UNIT

Bill

 

thanks guys for the info. I'll check these things out.