View Full Version : poor mileage and misfires

04-13-2007, 08:25 AM
ok so here we go again, still get 170 miles a tank

im still getting 170 miles a tank( 14 gallons)
it came over night, since this started i replaced the fuel filter,02 sensor, MAF, throttle body, installed samco tipand samco turbo to IC hose (one that holds DV) serviced my 007 DV, changed plugs and air filter, added exhaust and HFC, even installed another k04 to make sure that wasnt the problem. well the car boosts fine, but now i have misfire uner heavy load (over 11 psi) but the faults are not stored in the ecu you. the car bucks or bucks like its missing.
boost is holding 18 /19 and spike 20-22.
i looked at block 032 and it was -0.8 or maybe it was -8.0 and -10.1. when i changed the plugs they looked black so i know i must be running rich. do you guys have any ideas

04-13-2007, 08:39 AM
What type of outside air temps are you seeing over in chicago? Are you running colder plugs or stock heat range plugs?

The -8 to -10 for part throttle fuel trim isn't bad since it is just telling you how much fuel it has to pull back to keep the AFR at part throttle correct. Have you done any logging while the car has the issue?

04-13-2007, 08:56 AM
this has been going on since december so out side air temps have been from
0 - 70. i am running bkr6e plugs gaped to .28 i ran logs before, and have not in some time but here they are. and if you can tell me what logs to run i can do so tomorrow.

04-13-2007, 05:39 PM
sounds just like my issue. DOes it run fine under part throttle? My car is misfiring only at full throttle dispite how much boost (i can pull back on it). If you figure it out it my be my issue. I also have replaced MAF, ICM, COil packs, Sparks, TB. SIgh. G/L!

04-13-2007, 05:49 PM
On block 002, should the engine load readings be that low? Have any 003 and 020 logs?

04-13-2007, 06:59 PM
MrJackalope - yep only at WOT , ill post when i figure this out. good luck to you too

Mike- i have not logged anything else yet. and those logs are before i swapped the turbo and hfc. the old WG was loose so that might have had a role in those logs. tomorrow i will be able to log again. which blocks should i run ?

04-13-2007, 10:31 PM
Log block 015 + 016 to see what cylinders are misfiring.
Then log 003 + 031 together for o2 sensor readings

you dont need to log 032 since its long term and usually stays constant on a run.

But only do 2 blocks at a time to collect more data. Thanks Mike :) im becoming pretty good with vag i think. let him know if i missed anything.

04-17-2007, 04:20 PM
a4ce take a look at fuse number 29 in your car make sure its working fine. scan the car for which cly. is misfiring from then move that coilpack to another cyl. and scan again till you find the bad coilpack.

also when you put gas into the car does it start right up or take a few tries??

04-20-2007, 09:00 PM
wow we have the same problem!!

04-22-2007, 01:29 PM
no codes on the car, car starts right up after fueling. fuse 29 looks good
starting to think that my ecu / giac chip is bad. i let a buddy swap it in his car and he got the same bog, mis fire like feeling i was having. tonight i will put his giac ecu in my car and see if the bog is still there.

04-22-2007, 05:43 PM
i would check your coils again!! mine went bad after 3 weeks!!

04-23-2007, 07:00 AM
so its not the my ecu/chip, and wouldnt bad coil packs throw a mis-fire fault ?

04-23-2007, 06:50 PM
when my car missed/bogged sometimes the check engine light would flash and sometimes it wouldn't.. i would have to be in 5th gear going around 50mph and floor for a while for a code to get thrown.. i don't think i have an ecu chip in mine thoe (told there was) i was told by many of my co-workers (dealership) that sometimes the chipps go bad! my car runns great now that i replaced the bad coil..

04-23-2007, 06:54 PM
i let a buddy swap it in his car and he got the same bog, mis fire like feeling i was having.

ha ha missed this part!! sounds like it is your ecu.. i guess you'll know when you swapp the ecu's huh?

04-24-2007, 07:09 AM
so its not the my ecu/chip, and wouldnt bad coil packs throw a mis-fire fault ?

man this is annoying

04-25-2007, 07:01 AM
Maf could be bad...

04-25-2007, 08:25 AM
maf is brand new

05-01-2007, 04:58 PM
hmmm i a bad coil does throw a code, swap all 4 coils with someone you know and try again

05-01-2007, 05:10 PM
car is fixed and sold,
thanks guys

05-04-2007, 04:53 PM
Glad you found the issue. What was it if i may ask. I may have the same problem.

05-07-2007, 09:30 PM
yeah, car may be sold, but still having the same problem...
gas mpg is a little bit better, but not much..
plugs just replaced but still misfiring, NOT the coils, they were checked.