Off topic ..trouble with another Ford.plz help!!

[MUSTANGJOE]

:OT:

Hey guys..

Im having a problem with my winter truck. Its a 99 F-150 V6. Its ideling very funny. Its stays at about a line lower than 1000 rpm then every 3 seconds the idle drops to about 4 lines lower than the 1000 rpm mark then back to its regular position!!

What can this be? I tried cleaning the IAC but it still does it. Could it be the MAF or the TPS?

Thanks.

p.s- sorry its not stang related

 

[Az Pete]

http://www.ford-trucks.com/forums/index.php

Try looking here. Had lots of luck with this site.

 

[MUSTANGJOE]

http://www.ford-trucks.com/forums/index.php

Try looking here. Had lots of luck with this site.

Thanks..I just registered .looks good!!

 

[DTNODYA]

After you cleaned your IAC, did you disconnect your battery so that the computer could reset? If not, I'd do that first. FWIW, I was having a similar issue with my 2000 Mazda B4000 (Ford Ranger XLT) and I cleaned the MAF a few times with electrical cleaner ... didn't notice a difference. Then a friend of mine gave me a can of MAF cleaner and after I used it, no more idle issues. Weird I know ....

Reset your batt first tho' if you haven't .........

 

[MUSTANGJOE]

Thanks for the replys guys...

I was driving the truck today and my feet were cold so I switched the heater know to the floor position only and the surging went away..lol.

I usually keep it at the defrost setting for the windowshield. everytime I put it back at defrost the bad idling comes back/

Im guessing its a vacum leak?

 

[Mike97gt]

Thanks for the replys guys...

I was driving the truck today and my feet were cold so I switched the heater know to the floor position only and the surging went away..lol.

I usually keep it at the defrost setting for the windowshield. everytime I put it back at defrost the bad idling comes back/

Im guessing its a vacum leak?

The problem is that the A/C system is short cycling because it's low on freeon, so it will idle badly in the A/C and in the defrost positions. The A/C compresor runs in the A/C and in the defrost positions. When the A/C short cycles the computer can not adjust the idle fast enough so it starts to surge.

There is two ways to fix this.

1. Fix the A/C system leak and have the system recharged

2. unplug the low side cycling switch to disable the compresor.

 

[MBDiagMan]

Good diagnosis! You beat me to it.

 

[Mike97gt]

Good diagnosis! You beat me to it.

Thanks

 

[MUSTANGJOE]

The problem is that the A/C system is short cycling because it's low on freeon, so it will idle badly in the A/C and in the defrost positions. The A/C compresor runs in the A/C and in the defrost positions. When the A/C short cycles the computer can not adjust the idle fast enough so it starts to surge.

There is two ways to fix this.

1. Fix the A/C system leak and have the system recharged

2. unplug the low side cycling switch to disable the compresor.

Thanks...were is the side cycling switch?