slight hesitation

[SubieKiller3]

im getting a slight hesitation only on part throttle. mainly noticable at around 2500-3000 rpm in 5th or 6th gear. only mods are cobb sri and turbosmart bpv at full recirc. afr seems normal so i dont think its a fuel pump issue. boost vac seems normal and checked for boost leak so dont think thats the issue either. have only 8,000 miles. maybe i got some bad gas? gonna try and clean the MAF sensor tomorrow and see if that helps at all.

 

[matsuda]

What are the LTFT's?

 

[Darth Vader]

Check every vacuum hose. I've had a number of hose-leak related issues on my 08, including what you describe, which was the vac hose to the BOV leaking. I've replaced the spring clamps with worm clamps on that and no more leak.

 

[CWPspeed3]

I think you may be looking to far into it, if your in 6th gear at 2500rpm and theres hesitation while accelerating then downshift.

 

[funksilver07]

Under 3k what your describing could be turbo lag... (dunno) This condition just started to happen or has it been doing this all along?

 

[absolutamente]

I have had mine for 60,000 miles now and am very familiar with how it drives. That said, my car also recently developed a stutter in higher gears when in the same rpm range. I have a smoking turbo and have partially written it off as fowled plugs, but I worry it could be something else. It's at the dealership now for the turbo and this issue, but I do not expect to hear anything too intelligent from them about it.

 

[SubieKiller3]

Under 3k what your describing could be turbo lag... (dunno) This condition just started to happen or has it been doing this all along?

well it just started happening. seems like shortly after my last oil change(at the dealership) hmmm....

im gonna go back and recheck all the vac hoses today, check the MAF sensor, and see if i can figure it out. for all i know it could just be my bpv needs to be adjusted but then again its felt and sounded fine since ive had it on and ive had it on for about 2 and 1/2 months.

 

[matsuda]

Check every vacuum hose.

...or check the LTFT at idle (which tells you if there is a vacuum leak, dirty MAF sensor, bad O2 sensor, etc.)

 

[HOBDisease]

...or check the LTFT at idle (which tells you if there is a vacuum leak, dirty MAF sensor, bad O2 sensor, etc.)

He meant STFT at idle.

 

[karl hungus]

im getting a slight hesitation only on part throttle. mainly noticable at around 2500-3000 rpm in 5th or 6th gear. only mods are cobb sri and turbosmart bpv at full recirc. afr seems normal so i dont think its a fuel pump issue. boost vac seems normal and checked for boost leak so dont think thats the issue either. have only 8,000 miles. maybe i got some bad gas? gonna try and clean the MAF sensor tomorrow and see if that helps at all.

i get the same thing when i blip the throttle to maintain cruising highway speed. first noticed it when i went to 1 step colder plugs.

tried blaming it on bad gas, dirty maf, and improper plug gaps (all negative).

i don't get how it could be an fp issue at such slight throttle.

 

[matsuda]

He meant STFT at idle.

No, he meant LTFT. STFT won't tell you anything.

 

[cymx5]

For those who don't suffer from acronymia...can you spell out (explain) LTFT and STFT. Mucho appreciado!
Is that read from a Dashhawk?

 

[SubieKiller3]

...or check the LTFT at idle (which tells you if there is a vacuum leak, dirty MAF sensor, bad O2 sensor, etc.)

so where exactly should the LTFT be at idle? whats a safe number?

 

[matsuda]

so where exactly should the LTFT be at idle? whats a safe number?

With a Cobb intake, it should be near zero.
Anything greater than +/- 5% would probably indicate a problem.

 

[matsuda]

For those who don't suffer from acronymia...can you spell out (explain) LTFT and STFT. Mucho appreciado!
Is that read from a Dashhawk?

This is a good paper:

http://www.accessecu.com/cgi-bin/do...ontrols to Make Fueling Corrections v1.02.pdf

 

[MSMS3]

i get the same thing when i blip the throttle to maintain cruising highway speed. first noticed it when i went to 1 step colder plugs.

tried blaming it on bad gas, dirty maf, and improper plug gaps (all negative).

i don't get how it could be an fp issue at such slight throttle.

Probably don't need to be running the colder plugs with your mods -- no AP tune, no DP, stock boost levels, if I'm reading your sig right. Just an intake and a test pipe would work better with hotter (standard heat range) plugs.

 

[SubieKiller3]

well i cleaned the MAF sensor, checked for leaks, checked the fuel trims and everything seems normal, no CEL, but same problem. so i dunno(scratch) maybe its the O2 sensor. think im gonna just take it over to the dealer and see if they will check that and replace it for me.

 

[Jacobra]

Its probly the electric throttle body. There is about a 3rd of a second delay between when you move the pedal and the throttle body adjusts. mine does the same thing and i dont worry about it.

 

[sierra248]

I have same issue on my 07 MS3, you guys ever find the answer to this?