Sluggish performance when hot

[X5V8RULES]

When i drive the x 4.4 2001 100 k miles on it in the morning it is fast and responsive . When the car gets warm (20 30 min of driving) it becomes slow and not responsive ( during little acceleration ( 1/4 of gaz pedal) i press the gaz pedal down further but the acceleration doesnt increase and the car requires more throttle than normal when i move off. No COde!!!! Any idea? Spark plugs , heat soak , maf or o2 sensor ( no code!!!) a lot of bmw owner suffer from this problem : http://blog.bavauto.com/1666/bmw-slu...ance-when-hot/. Also: Sluggish acceleration HELP!
Okay my 1992 bmw 325i has a tendency to get really sluggish off the line after you drive it for about 10 min or so. Its odd, right when I start it up its very responsive, but after driving for 10 15 min. the off the line acceleration becomes very low. Its like the rpm's shoot up normally but but the car doesn't agressively accelerate. I changed my O2 sensors, and spark plugs and still the same thing. Any ideas?

http://forums.bimmerforums.com/forum...php?p=22661725

[dave the viking]

I don’t think it is the spark plugs, I do thing that you may need to replace your air filter. When you first start out your air pump may be still on and the throttle plate may still be opened up still. As the care gets warmer the air pump gets turned off and the throttle plate closes a little.
I would also flush out your radiator and also add some red line water wetter. It will help keep your truck cooler. I would also check your cats out to see if they are plugged. You can kick them to hear if they rattle. If so you me need to replace them.
For your air filter I would recommend a K&N air filter.

[X5V8RULES]

THX for the advice! i will change the air filter next week. i forgot to mention that im getting a horrible gaz mileage 6-7 mpg.

as for the cats i cant hear any rattle while driving the car

and i will replace the spark plugs for the first time

[Nik]

You have to kick the cats themself to hear them if they rattle

[X5V8RULES]

When you first start out your air pump may be still on and the throttle plate may still be opened up still. As the care gets warmer the air pump gets turned off and the throttle plate closes a little.

Sorry . it is normal \ good thing???



i didnt understand how replacing the air filter would solve my problem: the air filter is ALWAYS dirty ( when the car is hot or cool )

[X5V8RULES]

could it be also a dirty fuel filter?

[Nik]

air filter may be dirty anyway, but throttle is opened up to full and + pump is on so it's using more force to get the air in!

[X5V8RULES]

More information: i havent changed anything yet but i can hear a little whistle sound when revving the engine . I think it s a clogged catalytic converter (as you said) but i dont get cel light!!!!! Is that possible ?? Nb sluggish performance when hot and the x goes a little faster when smaching the gas pedal ( the x is not very responsive )

[Nik]

Why not lift your car, and kick the Cats. then change the filter, it wont hurt. it is a cheap fix and will be good anyway. then if it presists, go to GT1 indy and get the codes read.

[X5V8RULES]

but im not getting any code on the dashboard !!!!