Anybody having issues with a rough idle on start up with the new 5.0? When she cold starts, there is a very noticeable shake that can be felt in the driver’s seat. I opened the hood to watch the engine “rock” during the high idle vibration. The dealer states everything is fine……of course, 1500 miles on the OD and it is not show8ing any codes......But these new motors with all their advanced data sensors should have a silky smooth idle sitting a 5300 lb truck. Anybody got an idea?

 

Mine is as smooth as can be. I sometimes have to check to see if I have stalled at stop signs/lights due to it being so smooth and quiet at idle.

 

It does not have to be very cold outside for me to "feel" the engine on the first startup in the morning. It smooths out as I back out of the drive. I figure it is just rich at first. It is not something I can hear, but I feel it. It will turn over 17,000 today in 6 months. My fuel mileage is excellent, engine is perfectly quiet and runs great, so I am not concerned about it. I am averaging between 19 to 20.5 mpg week after week, up to 22.7 on the highway with cruise set at 70 mph. The truck as averaged 19.4 for the full 17,000. I don't want anyone touching it!

 

What brand and octane fuel are you using, and do you know how much ethanol content it has?

 

I assume you're asking the OP?

 

Yes. I know you only use good stuff.

 

First, since I live in Florida, my definition of "cold" may not really mean COLD! I'm just saying the engine has been sitting overnight. She runs very smooth the rest of the time and there is no vibration once the engine comes off of high idle, so it is not like the truck has a bad engine mount. I actual use Costco gas and mix the tank with a 40-60 blend of Super (93) and regular (87) since Costco doesn't offer a mid-grade. It has had a tank or two of BP reg as well. I have a hard time believing that Ford would build an engine that goes in a truck that really needs anything more than 87-89 Octane. I can only imagine what the cost would be to fill it with full 93 Octane..............

 

It needs only 87 octane, but you should use a gas with a good cleaner, such as Chevron and Texaco that have Techron. Shell is good, don't know about others. I would not run Costco if it were me.

 

Costco gas is pure crap with 10% or more ethanol. You don't need more than 87 octane, real or mixed midgrade is a waste of money.

 

Be carefull,I remember from 2004-2008 form this problem is from a leacking inyector and can make your engine to "desbielar" (sorry can't remember the word in english) you have to go to your dealer.

 

My '11 5.0 has been silky smooth from -10* to 100*+ in the 18k I have on it. Runnin 89 octane e10 since the only non e10 gas in iowa is 91+....my truck seems to like the BP 89 octane e10 gas better than any other tho....