My 5.4 liter engine idles pretty badly at 1500 rpm and I was wondering if this was a common problem or something I should be concerned with. I don't think it is the same vibration problem most people have because it happens with the truck parked and the engine in neutral. It feels like the whole truck is shaking side to side but above 2000 rpms it seems to go away. Also stopped at redlights I feel an intermittent but noticable shudder.

I've taken it into the dealer and they've told me there were no trouble codes and they even reprogrammed it. This makes me think that the engine is somehow unbalanced.

This is the first vehicle I've purchased brand new off the lot and I'd think it would idle nice and smooth, especially since its a V8. Should I try to complain louder for a fix for this? Any suggestions would be appreciated.

 

Sounds like a drivetrain problem. I have an '04 FX4 5.4L with 16k miles on it and you can't feel the engine at all unless you rev it up and it's not shaking at all then.

 

actually my 5.4 has a noticeable roughness at about 1500 also-especially when cold. i feel that it is a slightly lean condition (emissions?). i live with it because i do not notice it other than the first start of the day and do not want the dealer tampering with it.
jim

 

First of all, your truck should idle around 600 RPM not 1500. I had a uneven idle with my '04 and after two trips to the dealer they replaced the throttle position sensor and its been fine ever since. The truck idles very smooth and while driving is very quiet and smooth also.

 

Yes it idles around 600rpm, but when it is revved up to around 1500 rpm the vibration is the most pronounced. Whether I rev the engie i idle sitting parked or am driving and it hits that speed, I can feel it shaking. It happens when fully warmed up too. Seems to me like something is unbalanced. I'm going to take it in this Friday and I'll let you know what happens.

 

My Truck 04 scab fx4 idles at about 500-600 rpm