Hessitation and Stuttering at 25-35RPM

[MRWILT]

I am getting some slight hessitation and stuttering between 2500 and 3000 RPM under moderate to heavy acceleration. I dont think its my HPFP cause i dont get long delayed startups and I just took my car to the dealership to get the fuel system cleaned. any ideas? I know whatever is wrong is minimal cause the car for the most part runs fine but its just not 100% and that irritates me. I can feel it but when they run it at the dealership and check the computer its not throwing any errors so they dont do anything even though the tech that rode with me could feel it.

[chachacha28]

i had the same symptoms when my hpfp died a week ago. always started right up, drove fine under light throttle, drove fine in map 8 (economy mode on jb4, no boost) i wasnt even pulling fuel pump codes at first. it got worse and worse over the course of a week, to the point that it took about a minute to start, and was barely driveable.

[MRWILT]

uggh great! well if its going to happen id rather it just go ahead and get really crappy so that I can just take it in and get it fixed already instead of being in this slightly crappy car limbo

[chachacha28]

have you checked your codes? My car went from stuttering under 5+ pounds of boost, to un-driveable in a week.

[MRWILT]

no i havnt, i personally dont have the equipment for that and its been doing this for a while now. I bought it used about 3 months ago had about 47,000k and i dont quite know if it was doing it when i got it and i didnt notice or if it just gradually showed up. its not getting any worse or any better. just annoying cause when im driving no one notices it but me

[MRWILT]

I am going to take it to a car shop that specifically deals with mecedes and BMWS. i know someone that works there so maybe i can get someone to look at it that knows how to do more than just run a computer and can actually diagnose alittle better

[IZAGLO]

is it under warranty....if so take it back to BMW sounds like the HPFP

[MRWILT]

ya its under the CPO warranty so the HPFP is covered but ive taken it there twice already and they keep telling me no its not. its tough to take it over there when I have work and no other mode of transportation too. So frustrating

[MRWILT]

its like you have to wait for the car to literally break down before they do anything... plus i had to pay for my fuel system clean which is what they thought it was origionally. so if im paying for stuff i might as well take it somewhere that im not gonna get completely reamedon the price. anywhere that charges you $70 for oil change and $139 for brake flush is ripping you off IMO. Just had my SPK plugs changed too shoudl that cost $500 for some reason I think not.

[MRWILT]

my question is... if its the HPFP why would it only happen in the 500 RPMS between 2500 and 3000 (and its like clock work... only at that range no where else). would it be doing it all over the RPM range? Plus it doesnt do it so much when the car is cool. only when its just below 250 degeres

[Dackelone]

First thing I would do is change your spark plugs. Then if its still happening... I would either find a good indi with a code reader or buy one. I'd say its probably your plugs though. That is the first place to start.

[dtwyim]

Originally Posted by Dackelone

First thing I would do is change your spark plugs. Then if its still happening... I would either find a good indi with a code reader or buy one. I'd say its probably your plugs though. That is the first place to start.

Originally Posted by MRWILT

. Just had my SPK plugs changed too shoudl that cost $500 for some reason I think not.

I think OP says his plugs were just changed? Maybe not done properly? Wasn't there something about a specific plug you have to use even though the specs might be the same between plugs?

[Dackelone]

Originally Posted by dtwyim

I think OP says his plugs were just changed? Maybe not done properly? Wasn't there something about a specific plug you have to use even though the specs might be the same between plugs?

Well... hopefully his dealer used the correct plugs. But I have seen many posts when ppl change their plugs and use non-dealer bought plugs. There is something weird about the plugs BMW uses... and when you use an equivalent aftermarket Bosch plug... it can cause problems.

Still.., when trying to diagnose running problems... you start at the simple(cheap) stuff first. That would be plugs. Whose to say the dealer tech did not check the plug gaps or got a coil pack connector on correctly. That is where I would start first. That and checking for codes.


PS: OP a dealer should only charge an hour or two's labor at the most... plus plug costs. I can't see why they charged you $500 to replace your plugs. That is outrageous!!

[MRWILT]

ya ill suggest that to the indie shop ill be going to. What do you think about the fact that its only at the same RPM range any ideas? Also I got some adivse that maybe my intake valves need to be cleaned. any thouhgts?