New to this forum so Hello to all. Ive been reading that I'm not the only one with a new truck that idles rough. Its a 99 with the 4.6 ltr, only 6000 miles. Ive now had it in three times and received three reasons why it does it. I would appreciate any info on the tsb's that deal with this problem so I can go back with some ammunition...thanks

 

This a test .

------------------

 

Roscoe, check out the following thread. I just added an update to it. Might work for you.
https://www.f150online.com/f150board...ML/000676.html

There were a couple of other threads you should look at. Do a search on ROUGH IDLE in the ENGINES section and you should find them.

 

Roscoe, I just noticed that you're new to the list. Welcome!

Let me try to put together a list of possible causes from memory.

Wire harness touching A/C accumulator tank. Mostly a 5.4L problem, but couple of list members said it helped their 4.6L problem.

Bad TPS (Check Engine light would come on)

Bad O2 sensor. A/C condensate dripping on O2 sensor in exhaust pipe goes bad. It doesn't code until it fails, in the meantime, engine runs rough. Was mostly a '97 problem.

Bad Engine mounts. I believe there's a TSB for this.

Bad Exhaust system. There's a TSB for this too.

Leaking coolant from heater hose dripping on #4 plug. Mostly a 5.4L problem where coil on plug fails.


Hope this helps.

 

It also could be an exhaust system problem, rather than an engine idle problem. Does it happen only when the engine gets warm or gets worse when it gets warm? Is it a kind of bump and shimmy feeling.

------------------
2000 F-150, XLT SuperCab
4.6 V8, auto.
3.55 Limited Slip Diff.
Towing Package
Stainless ICI nerf bars
K&N Airfilter
Flowmaster 40 Catbck Sys.

 

Thanks for the responses, Cybweed thats dead on whats happening now whats the fix. A new exhaust system?

 

Well, I replaced mine with flowmaster catback system. It improved performance and also helped with the vibration some, but not all. Also, you might want to consider what type of gas you are using. I was using a cheaper brand and when I switched to chevron techron regular it also helped. I still have the vibration but have been able to reduce it with these two fixes. Now in regards to Ford this is a known problem and they are supposedly working on a fix for it. I would ask to have your regional trouble shooter look at your truck and see what they can do. Also, make sure you keep all of the documentation and do not let the dealer give you any bull about "not reproducable". You sit with them and force them to admit that there is a problem, and get them to document it in their computer. It is not normal for these trucks to do this, but if they can ignore the problem they will. My thinking is that it is a combination of factors, see the previous threads. The last thing that I am considering doing is installing the superchip. Good luck, and let us all know if you get a fix for your problem. We need the info.


------------------
2000 F-150, XLT SuperCab
4.6 V8, auto.
3.55 Limited Slip Diff.
Class III Towing Package
Stainless ICI nerf bars
K&N Airfilter
Flowmaster 40 Catbck Sys.
Colonel Bedliner
soon to add a TEKSTYLE
Quick Hatch and
Superchip