Just bought a 2000 F-150 V6. I changed the oil in it tonight and decided to go with Mobil 1 synthetic. In the owner's manual, under the hood, everything says to use 5W-30. I started the motor and it seemed to lag. I slowly drove it around the neighborhood and when I pushed the clutch in all the way and allowed the RPMs to drop, it would sink to 500 RPMs and almost stall. I live in Florida so I know the 5W-30 is a slightly viscous oil for our normally hot climates but not once was it listed that it was acceptable to use 10W-30 anywhere in the owners manual. Is the PCM/ECU just adjusting from the previous oil or did I royally screw up and need to bite the bullet on a $40 dollar oil change?

Worried in Florida,

Bradley

 

For put out TSB 02-1-9 that stated 5w-20 was now recommended.

 

I forgot that I had disconnected my battery terminals earlier yesterday to clean them and hence had reset the ECU... This is what happens when you breathe in two coats of wax dust in your garage... God I feel like moron for that one (Smiles & bows).

 

Maybe, but that recommendation is based on a minescule gas mileage increase while using it. I have my doubts as to the lubricity of 20 weight oil in VERY hot climates. (pure opinion though) I can't help but think about where these engines are designed and tested. They don't see 110 degrees at 99% humidity!

I think that 30W oil would be a little thicker under high temps, and that's why I use it.

 

10w-30 and 5w-30 are the same viscosity at operating temperature, why they can do away with 10w-30 alltogether. When cold 5w-30 acts like a straight 30w would cold, still thicker viscosity than a 30w at operating temp. As for 5w-20 , we ran it in 5.4L. pulling/delivering travel trailers in the Mohave desert all the time with no problems. We questioned it to our Ford Fleet Ditric Rep. ,not realy sure he even seen how they are designed, and he said they were designed and tested to max rated capacity for power, economy, and longevity, and was told were the same and/or better useing 5w-20 over previous recomended 5w-30. But was still OK to use 5w-30. Guess we are just used to seeing thick oils from the past, I've never done any test to tell if 5w-30 is just massive overkill in viscosity

 

That's all fine, but I'm not gonna put 20 weight oil in my truck. I know 10W30 doesn't hurt it, cause I've used it for years. I run 20W50 in my jeep, with a 20% solution of 120W additive, and it runs great. If I put 5W20 in it it would probably pour out of every seal on the motor.

 

Doubt it's an oil vicscosity problem. If there are no codes(CEL), I'd say an IAC failure. Type IAC into the "search" box. Do some reading.

Good Luck (and let us know how it's resolved)

 

Why does everyone scream "IAC valve" the second something goes wrong in their car; it's like screaming "Ritalin" for a hyperactive child. I've seen this notoriously across Honda forums as well. Best piece of advice, don't f*ck with your IAC unless your physician tells you to.

PS- I posted above saying I had forgotten that I had reset my ECU... Hence, the motor had to learn to idle again. If you search all of my posts, you'll find proper instructions on how to do so.

 

Because a clogged IAC is a very common problem for these trucks and can cause problems similar to yours. Not to mention, there's nothing wrong with cleaning the IAC...no harm can come from it, its extremely easy to do and hard for just about anybody to screw up.