I have a 2002 F150 EXT Lariat with the 5.4L.. When I start the truck it has a rough idle that is felt in the truck. I have had it to two separate Ford dealerships where they put it on their computer and I was told the scan showed nothing and that it is simply due to the Fuel Injectors. I was told some cars run a little rougher than others as a result. The Dealer here in Corpus Christi reccomended a fuel system clean which I spent the money for since I was not given any other solution but it still idles rough after this 200.00 treatment.This truck has not done this since it was new, I am not sure what the mileage was when it startd but it now has 45000 miles on it and I am getting annoyed with it. Any recommendations or is this something I am going to have to live with.

 

Is the CEL on? Did the dealer check for DTC that may have been pending? If so, what codes are there.Any information that you can provide will generate response from many knowledgable forum members.

The problem could be a cracked PCV hose at the rear of the intake manifold. This is a common cause of rough idle because it can produce a large vacuum leak. Usually if this is the case, there will be a CEL.

 

i have the same problem.....when the engine is hot and its idling, the truck has a slight vibration that i can feel...no codes came up either

 

I am n ot sure what CEL is but the truck threw no codes and I have not checked the hose

 

that is the same time mine does it and they attribute it to the injectors but I have seen on here a few times the PCV hose being a causal factor

 

Sorry for the ignorance but what is CEL and DTS?

 

Check Engine Light = CEL

Diagnostic Test Code = DTC

 

never had a check engine light and it never threw any codes, everytime it has been checked it has been clear of a code.

 

DTC= diagnostic trouble code,
CEL is aka MIL = malfunction indicator light

your problem could be a couple of things, it very well could be a dirty or partially clogged injector. When an 02 sensor reads its bank, it cant tell if any lack of or excess 02 is coming from any 1 cylinder in perticular, just that bank in general. with that said, you could also have a bad 02 sensor. You could have a bad plug wire or plug, it does happen, and they only will misfire at random.

another problem that can go along with the dirty injectors is the electrical connectors will become corroded or have tiny arcs between the contacts. simple solution/test, put some diaelectric grease on the connectors, it makes better contact.

It could be the idle air control motor... simply controls air flow when at idle. You could have restricted air flow in the EGR system, but both of these things SHOULD set a trouble code.... unless the malfunctions are too few and far between and only you notice.

A lot of codes will not be set unless there are 2 consecutive failures, if you only have a failure when the truck is hot, next time you drive it maybe you dont get it hot enough, no misfire, so you wont get a code.

but dont run out and shotgun parts, see if someone can do the injector cleaning cheaper, its worth it.

 

This is quite normal. My truck has done this since I bought it. There was a TSB on it where they added softer motor mounts and put some damper weights on the ehaust pipes. It didn't really help. I'm so used to it that I don't even notice it now.

 

ok thanks....but the funny thing is, my dad has an 02 screw with the 5.4 and that thing is smooth as can be....not a vibration at all or anything

 

Same here. I bought my '03 brand-new off the lot and it has idled rough since day 1. It runs great, and no codes come up about it.

 

Hi
I know this is a late reply, but I am getting several codes refrencing the O2 sensors... does this mean I need to replace them? Its pretty costly...
THANKS!!

 

Not necessarily. What DTCs are you getting?

 

I am getting:
PO137
PO136
PO141
PO155
PO156
PO161
P1151
P1152
I borrowed a scan tool from Autozone and erased them from the PCM, drove the truck around the block (check engine light didn't come back on), turned the car off, hooked the scanner back up and P1151 and P1152 came back. So I erased the codes again, backed up out of the driveway and back in, turned the car off and rehooked the scanner. This time no codes were present.
Could I have gotten those codes from having a bad battery? We got a new battery in it now...?
The truck only has about 58,000 miles on it so it just seemed weird for the sensors to go bad so quick.