Have lusted after the F150 ever since the new body style came out. I waited for the old ride to hit 250k, and took the plunge. Many nights of lot shopping and internet searching brought me to exactly the truck I wanted. I bought my Supercrew new in August of 2007.

The F150 does not disappoint. I love everything about this truck, except one thing. When I start the truck cold, the engine shakes like a muscle car with a hot cam. About 30 to 60 seconds later, the RPMs drop and the engine smoothes out for the most part, but the rough idle never quite goes away.

The Owner's Manual says:

"Hot Weather Starting (flexible fuel vehicles only): If you are experiencing a rough idle or rolling idle after start up with the outside temperature above 80 degrees F, the idle should improve within 10 to 30 seconds. If the problems persist below this temperature, see your authorized dealer."

Well they did, so I did.

After several trips to my dealer where I left the car for 3 or more days each time, they said they feel what I feel in the rough idle, but it must be a "running characteristic of the truck" because it was throwing no codes. No codes = No problem (?). Another Mech said "It eventually goes away". A dismissive answer that was hardly scientific.

They reflashed the unit twice with no change. I asked them to show me another new vehicle on the lot that had the same "running characteristic". They showed me two. One fresh one, and a salesman's demo. Both trucks had the same problem. I asked them to check to be sure there were no mechanical problems (ie: vac leaks, electrical issues, fuel system flukes). They said it all looked good. Dejected, I took my new toy home and have been simply "dealing" with the crummy idle ever since.

The rough idle at start-up happens at all temperatures, although it is noticeably worse above 80 to 85 degrees. Once the engine is warm, the idle smooths somewhat but never quite "purrs". I know it can run well because after a short trip on the interstate, when I come down the off ramp and sit at the traffic light, the engine is idling like silk. Drive around town for a few miles and the rough idle is back. Another funny thing .... when I sit with the engine running in park, and slowly increase the rpms, the engine starts to run noticeably rougher at 1200 rpm, then rougher yet untils it peaks at 1500 (with a pronounced "shimmy"), and gradually runs smoother until it runs "normally" at 1750.

Most of my driving is low speed local stuff. Lotta stop and go. How the truck idles is important to me. I live in Louisiana, so there's plenty of days above 80 degrees, making for a lot of rough starts. I take a weekly run up the I-10, about 180 miles round trip, so I get to see the engine running at its best then.

I guess if someone can explain the logic of a shaky engine I might buy it, but years of vehicle ownership and shade tree wrenching have taught me that a rough engine is out of tune or broken. FORD is telling me this truck is neither. I can't imagine FORD would design the truck to run like this. I worry that by not dealing with what I feel is a problem I may be damaging my new vehicle by continuing to drive it.

Interesting ... when I went to the dealerships for test drives, the salesman always brought up a running vehicle. I never had the opportunity to walk out to the truck and start it myself with the sales person. I never noticed any of the test trucks idling rough, not even when I picked mine up the day I bought it.

If the truck runs rough because FORD had to incorporate some oddball tuning to meet fleet emissions, I get it. Just tell me the truth so I can go find someone who can set it straight. If a performance tune will take care of all of this, I'm there. I love this truck, and I want to love how it runs too. Any good thoughts on this would be greatly appreciated.

 

I noticed a shake myself.. I had it checked out they said the 5.4l is known for it.. mines not terrible. but to me i though the truck had a miss or a bad wire. or something..

 

my 07 doesnt do that, neither does my buddy's 07. hmm i'd keep bitching about it, you never know what could be wrong with it.

 

Thanks for the input y'all.

I think this might be an issue for the engine forum. Movin' on over.

 

What gas are you using?

 

For what it's worth, my '08 5.4L Lariat sounds rough at start up as well. I would bet the engineers set 'em to start with low idle and lean (air/fuel mix) to:
1) save wear on cylinders that may have cold, old, or NO oil in them at start.
2) Save gas at initial start up. Hopefully no one out there still actually revs their engines to "settle it into idle" these days. Lets let the computer handle the warm up and settle down to normal idle folks!
3) Create a booming market for tuners and other aftermarket goodies to juice up the truck beyond the "stock" ratios.

I will say this that if it bugs you enough, fix it or get it re-tuned. I traded an 07 Nissan crew cab that had a funky air conditioning compressor clutch noise that drove me crazy and that the tech at Nissan dealer couldn't resolve. Now, that was an expensive way to solve a simple problem. :o

 

I used a tank of Premium back when I first noticed the rough idle, in case the local regular was NG. It seemed to run better, so I've been using 89 octane with a tank of regular every few fill-ups ever since. I just went back to full time regular a few weeks ago and it runs about the same.

I called the guys at Troyer, and they said they could get any 150 humming as long as there are no existing mechanical issues in the way that should be fixed under warrantee first. The dealership said there's nothing wrong with this truck. Assuming they are being straight with me, a tuner's touch sounds like it could help.

 

You're exactly right.

 

My 07 does not do that, and as for hot weather starting I live in az and startup in 110+ degree weather

 

Upon cold start up the RPM's shoot up for a bit, then they come back down, in hot weather + longer in the winter months! As far as rough, I'm confused on that, when my RPM's drop back down, engine is smooth as butter......

 

My dealer told me it was common with the 5.4l that there is a little ruff idle. i mean mine is really not that noticeable. but me i notice it. my rpms dont jump though

 

I guess with the multitude of parts that make these things run, and the range of what they call "within spec" for each part, our trucks are all going to run a little different.

Has anyone run premium fuel on a regular basis?

 

GBCrewser - Stealth is correct about the tuner. I had to take my truck in for warranty work on Tuesday. Troyer suggested that I return it to stock before the service just in case the dealership would "mess-with-it".

Just got it home yesterday evening and I can't wait to reinstall the performance tune. I had forgotten how poorly these beasts run on the stock tune. The truck hesitated, stumbled and shifted poorly all the way to and from the dealership (120 miles round trip). I had to relearn merging on the interstate because the "punch" is gone.

Order your tuner from Troyer, install your favorite tune and enjoy.

Kenny

 

You really get no benefit from running a higher octane than your truck is able to use in it's tune. It is tuned for 87 so that is what you should run. A higher cotane messes up the time of cylinder fire and can leave extra deposits. I am running 93 octane, but I have a custom performance tune for 93 with the Gryphon tunes. I also have an 87 Performance tune, and I switch back and forth. You really need to get some custom tunes to be satisfied.