Has anyone experienced a unusually rough idle?? That is, while the truck is in Drive, but at idle speed. My tach usually stays between 500 and 650RPM, however it idles so rough that it sometimes shakes and rattles the dash or truck.

I am taking my truck in the shop tomorrow AGAIN for the same problem, can the idle speed be raised slightly?...the problem seems to go away then. For example, if I apply the gas slightly with my foot on the brake.

They say they all idle that rough, but I bet if I started up one of the new ones on the lot it would be smooth...

 

Either the MAF is dirty, a plug has gone south, fuel filter dirty, injector dirty, etc.
Good Luck

 

LightninSVT,

My 2001 L with 12K miles on it just started to idle rough just how you describe exactly. Raise the RPM's by 100 and it goes away. I am taking mine to the dealer tomorrow. Let me know what they tell you.

Howard

 

May be a dirty/worn out Idle Air Control or a vacuum leak???

Dan

 

Seeing as how the timing is jumping from 11 to 30 degrees advanced at idle one would not expect a very smooth idle. Age does make it rougher as does factory plugs after a little while. It does get a little smoother after plug change but not much.

 

Howard,

Thats what the service manager said, that they might be able to raise the idle by 100. Not much more or it would throw the service engine light on. But if they put it up 100 then it should not, then both the computer and me are happy

 

ding ding ding! Got the truck back this afternoon, idle control valve. They are also checking to see if there are any TSB's for the MAF they told me, don't know what that will do. I already got the newest update for the computer when it was replaced.

 

Ok, this is getting annoying....I must have posted problem solved too soon. The truck is still doing the same thing, if not worse than before.

Could it be the plugs? the truck had a superchip in it from the previous owner i believe...

Anything I could suggest to the dealer so i don't have to go back a 4th time!!!??

 

If I was too just go ahead and change the plugs to see if that solved the problem....

Which plugs would you guys suggest, i'm thinking TR5's or the Denso's?

The truck is fairly stock

 

I say a plug or plugs.

 

If you can pinpoint when it started like after some service was done or you changed plugs or any kind of work under the hood then I would look for a vacuum leak.

 

Just a suggestion if there were any vacuum leaks or if the
engine was misfiring the check engine light would come on
so take a good look at the engine mounting, trans and exhaust
mounting for possible cause without being able actually feel
concern hard to diag. sounds like something is causing a
vibration??? a good ford tech should be able to determine
if it is a drivability concern or a vibration concern what do i
know i just a work at a ford dealer wish i was closer so i could
help

 

I think i've pin pointed it somewhat....It seems to start to vibrate more when I have the panel heat or defrost on, it doesnt do it when on floor.

I was told that this was the idle control valve or whatever it was they "said" they replaced. I received no paperwork....

You think I could convince them its the plugs and get them to install new ones under warranty? After all...it could only help the rough idle problem they can't seem to solve after 2 visits already.

modularman: I wish you were closer too, maybe i could get this problem resolved. Its embarrasing when people in the passenger seat ask what that noise is?

 

good luck getting them to replace plugs. my dealer wouldn't do it for my '01 so i had a local guy (rtkilla) help me swap my plugs. we used the ngk tr5s and now everything is smooth as silk. who knows if it was a plug, or a pack not being seated properly, but it's worth it to do it yourself and do it right.

 

[QUOTE]Originally posted by Crued
good luck getting them to replace plugs. my dealer wouldn't do it for my '01 so i had a local guy (rtkilla) help me swap my plugs. we used the ngk tr5s and now everything is smooth as silk. who knows if it was a plug, or a pack not being seated properly, but it's worth it to do it yourself and do it right.

[/QUOTI agree 100% Ther are jobs that I would much rather perform myself than to continue the stress of leaving it at the dealer time after time.Just my .02