A little help please, misfires.

[Rookie48]

...and I think the oil consumption MAY be related if this is indeed a lean condition.

My theory - lean cylinder condition allows for some oil film to be burned off the cylinder wall.

[Ricky Bobby]

Originally Posted by Rookie48

At this point I'm somewhat convinced there is a small vacuum leak at high vacuum conditions with the throttle just off of closed. But finding it is a buggar!

-If the VCG and 15 grommets were replaced
-The lower intake elbow is good (check the elbow for cracks and the 2 vaccuum hoses and replace those as well)
-Throttle body is clean and gasket is good
-ICV is clean and mounted securely
-CCV is replace with good parts and hoses are secure on the CCV, and dipstick guide tube is clean/clear for the CCV drain
-vaccuum hose from the EVAP canister is good (there is a vaccuum tube at the back of the intake manifold
-If fuel filter was replaced, the small vaccuum hose is not broken
-Coilpacks and plugs are verified to be good
-Battery is in good condition (needs enough voltage to fire the coils)

I'm pretty much out of low throttle high vaccuum misfire solutions lol

Good luck to you guys

[Awntchi]

SarTech, apologies if I've missed this info somewhere in the thread: Is it a petrol or a diesel engine you have?

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[SarTech]

Petrol.

[Awntchi]

Ok, I've asked a friend who works at volvo (15+years) as mechanic and he told me that he used to get a lot of cop cars in with the same symptoms as yours...the remedy was to basically change spark plugs and O2 sensor, and just check that all other stuff are ok (ignition coils, leads etc). Then take the car out for a very hard run...accelerate hard on as many gears as the road allows basically. This clears the buildup of all the carbon (swedish police are cruisers and rarely push the cars) which causes misfires etc. Also, you can actually see the the amount of carbon coming out when doing so.

It might sound unorthodox and sure it's not bmw but he has been successful every time with Audi, volvo and Saab.

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[Gray035]

Hate to revive this old thread, but like so many other similar ones it there is no indication whether the issue was ever resolved.

So SarTech, did you ever resolve your problem? Or did you get rid of your X5?

I have similar issues to the ones you described, and I'm looking for guidance.

[Rookie48]

Try switching to a good grade fuel... after all the $hit I did with my X5, a freak twist of fate seems to have solved my issue. I was using Gulf 92 octane fuel with no ethanol added for over a year. I trusted the gas station, no reason to beleive it was poor fuel. One day, I had no choice but to put in a tank of Sunoco Ultra 93 octane (with ethanol). Within 100 miles, the issue subsided. Since then, Sunoco fuel only, and the misfire issue has not re-occurred!

No clue why, but it resolved my issue for now.... worth a try!

[StephenVA]

Originally Posted by Rookie48

Try switching to a good grade fuel... after all the $hit I did with my X5, a freak twist of fate seems to have solved my issue. I was using Gulf 92 octane fuel with no ethanol added for over a year. I trusted the gas station, no reason to believe it was poor fuel. One day, I had no choice but to put in a tank of Sunoco Ultra 93 octane (with ethanol). Within 100 miles, the issue subsided. Since then, Sunoco fuel only, and the misfire issue has not re-occurred!

No clue why, but it resolved my issue for now.... worth a try!

I can help you here. If you pull a fuel sample at the fuel rail and place it in a glass container (SEE MOTOR SERVICE MAGAZINE FOR REAL LIFE EXAMPLES and test procedures), you will discover that water and ethanol mix is way beyond the ability to burn cleanly. ADD injector cleaner/dry gas additive to 1/2 tank, repeat until gone....Or drain tank. Most of us pick up water and poor fuel mixes from stations with low volumes or "discount stations". Real life issue all over the USA especially in the colder areas due to seasonal fuel change overs.

[StephenVA]

still out there?

[JimG]

SarTech, did you ever resolve this problem?