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Title: felt like something "let go" Post by: killpop on June 12, 2021, 02:05:47 PM Been chasing misfire codes. On a test drive after replacing the MAF, I had what I would describe as a boost hose coming off. During acceleration from a stop light, power suddenly dropped off and car remained sluggish until I got home. Was expecting to find something obviously wrong under hood but no issues found. I was logging when this happened but I am not sure what to look for. Some suggestions on what to log would be helpful. Hoping somebody can take a look and tell me what they think.
Ongoing problem: Sometimes on a cold start, engine will misfire badly at idle until it reaches normal operating temp and has a key cycle. While this is going on, will feel like its only running on half it’s cylinders. Seems like it does this more when the weather is colder or after it rains. Sometimes the car doesn't idle well and will go into some kind of limp mode with 5 PSI boost limit. Other times, the car runs perfect. In the logs I posted, “event” and “pre event” were taken on the day in question. Other logs are before the MAF replacement. The screenshot of the codes were also taken before the MAF. Misfire codes would be on different cylinders, truly seem random. Car is an 03 GTi 1.8T (AWP) New bosch fsi coils, new bosch MAF Have previously smoke tested the intake (cold and hot), no leaks found. Car is stock other than my noob tune. I don’t think this is the issue as it ran great for a long time prior to these issues. Will post file if anybody thinks it will be useful. Open to any and all suggestions, need help. About to set this POS on fire. edit: for some reason, its not letting me add the logs, will try to get this sorted Title: Re: felt like something "let go" Post by: killpop on June 12, 2021, 02:25:48 PM not sure whats up with the site, had to put the logs on my google drive. here is the link, I appreciate your patience. I really do need help with this.
https://drive.google.com/file/d/1skphk3psl8slRFsGLKRF2e1Aimny9F0Z/view?usp=sharing Title: Re: felt like something "let go" Post by: killpop on June 15, 2021, 11:30:17 AM I have been looking through the logs more and I wanted to know if this may be a clue as to my underlying issue. These two screenshots both show a cold engine start, idling for a bit in the driveway and then driving around a little. First one is from when the car is acting normal, second is from when its misfiring and running rough.
I guess most of this looks pretty normal except for the odd temperature dip after its already up to temp. Even stranger, that dip is when I was stopped at a traffic light so doubtful that is was caused by a loose wire jiggling around. Title: Re: felt like something "let go" Post by: killpop on June 15, 2021, 11:30:56 AM This one is weird, it shows a very erratic temperature climb and that the system is lean. I am just not sure how much I can trust this data. Obviously, engine coolant is not fluctuating in temperature at that rate. I might suspect flow interruption but I doubt that there are air pockets in the system; coolant system doesn’t leak and hasn’t been open in a long time.
Is any of this significant or am I just chasing my own tail here? |