engine rpms fluctuates at startup for few seconds

[OrangeCrush]

Any ideas?

Seems to happen more when it's warm than cold. Engine starts up fine, then seems to stutter for a second or two. After that, it's completely fine.

Got 70k miles, changed the fuel filter about 20K miles ago.

Any suggestions?


Thanks,

Mark

[PARAGON]

Try some MAF cleaner on the MAF sensor and also do the throttle body.

[PARAGON]

This last time I used the same cleaner I used on the MAF. There's something about MAF cleaners being oxygen safe or free or something. Anyway, I bought specific MAF cleaner and just used that same stuff in the Throttle Body. I had used it on our Denali that has the same 6.0L in it because it was doing the RPM fluctuating. It immediately stopped doing it and the mileage immediately jumped.

It's CRC MAF cleaner.

[ree]

Freaky. Mine started doing this 5 days ago. It only does it after sitting hot for a while. It'll do it for about 20-30 seconds and stop. Or a blip on the throttle will make it go away too.

Since a new tank of gas it's been happening less and less, so I suspect that I had some funky gas. I stopped at a discount station I've never been to on the previous tank.

But I say x2 on the MAF and the throttle body. It's easy to do. I had a similar problem on my last vehicle and cleaning these made it go away. Crazy thing is that there's something like 60 things in the SI manuals that are listed as possible causes for this issue. You might as well try the easy ones first.

[OrangeCrush]

Took the air intake box off and cleaned the throttle body. I also sprayed the mass flow intake. I'll find out tomorrow how it behaves. I went for a short test ride today and it seemed fine.

If it doesn't help, I'll pull some codes tomorrow.

Thanks for the help.

Mark

[PARAGON]

Originally Posted by PhilD

I just cleaned my throtrle body with some de-carb. Watch out for the fan, t hurts!

You didn't use the straw, did cha