Yes, Another Misfire Thread - With A Twist

[LSV8ATL]

OK, I'M NEW TO THE SITE, AND I NEED SOME ADVICE AS TO WHAT I SHOULD DO. I HAVE AN '02 LS V8 THAT I BOUGHT A YEAR AGO IN MAY. SO I STARTED NOTICING SOME MISFIRES AROUND 45 MPH, YOU KNOW THE USUAL STALLING AND LOSS OF POWER. SO I THEN TAKE IT TO THE DEALERSHIP, AND THEY SAY CAUSE OF MY PROBLEM IS A BAD COIL AND SPARK PLUG IN CYLINDER #1. THEY ALSO RECOMMEND A PCM REFLASH? SO I START SOME RESEARCH AND DECIDE TO DO THE REPAIR MYSELF. UPON REPLACING THE COIL AND PLUG, I NOTICE TONS OF OIL IN THE SPARK PLUG WELL. SO I PUT EVERYTHING BACK TOGETHER AND THE CAR IS MISFIRING LIKE CRAZY. SO I TAKE IT TO THE DEALERSHIP THINKING THAT THE PCM REFLASH WOULD SOLVE IT, AND THEY TELL ME THAT IT WOULDN'T. I ALSO MENTION THAT I HAVE OIL IN THE WELLS AND THEY TELL ME THAT THEY WOULD HAVE TO CHARGE ME AT LEAST 150.00 TO DIAGNOSE THE PROBLEM. SO I DO SOME MORE RESEARCH AND REALIZE THAT I NEED TO REPLACE THE VALVE SEALS AND GASKETS ( WHY WOULD THE DEALERSHIP WANT TO CHARGE ME TO DIAGNOSE WHEN THIS IS SUCH A COMMON PROBLEM?). SO I TAKE IT TO A FRIENDS MECHANIC AND HAVE THE SEALS REPLACED. I AM HAPPY TO REPORT THAT MY BABY RUNS MUCH BETTER, BUT I STILL DETECT A SLIGHT MISFIRE WHILE IN PARK, AND EVERYONCE IN AWHILE WHEN I'M TRYING TO ACCELERATE. ALSO I NOTICE THAT MY HEADLIGHTS AND ODOMETER READOUT FLICKER VERY SLIGHTY NOW. WHAT IS THIS? AND ALSO, WHY WOULD THE STEALERSHIP RECOMMEND A PCM REFLASH FOR A COIL AND PLUG REPLACEMENT? PLEASE HELP, I WOULD LIKE TO GET MY BABY RUNNING PERFECTLY SO I START PUTTING MONEY INTO PERFORMANCE INSTEAD OF REPAIRS!

 

[Quik LS]

Could be an alternator - many of us have replace them after a couple of years. Usually the problem shows up worse under braking - dash lights go dim, radio cuts out, ....etc

I'm sure others will chime in with thoughts.

BTW: try to not typing all in one big run-on paragraph - it is hard to read.

 

[machlsowner]

CAPS = Annoying and hard to read.

They charge the diagnosing fee on every ticket that isn't an oil change, brake job, tires, etc. Anything that is not a "normal" service item has to be diagnosed. It is a way they make money.

 

[LSV8ATL]

Sorry about the one long paragraph guys, I'll try to keep that in mind next time. So what do you all think about the pcm reflash? I haven't noticed anyone else saying anything about this being necessary with a coil and plug replacement.

Owning this car would be sooo expensive without this forum. You guys have saved me alot of money so far and it is greatly appreciated.

 

[Quik LS]

I have never heard of a PCM re-flash fixing this type of issue - if a PCM code base had a mis-fire issue - there would be 1000s of cars effected....

but - you never know.

 

[2001LS8Sport]

The PCM flash is unrelated to the miss. It's just an upgrade that's out there and available for you. One thing it did on my son's car is improve the shift quality of the transmission significantly. He also claims it helped his mileage. As long as you're not running a custom tune, I'd let them do it....FOR FREE! I wouldn't pay for it....

 

[GWL]

The PCM flash is unrelated to the miss. It's just an upgrade that's out there and available for you. One thing it did on my son's car is improve the shift quality of the transmission significantly. He also claims it helped his mileage. As long as you're not running a custom tune, I'd let them do it....FOR FREE! I wouldn't pay for it....

My new 04 got a re-flash a several months after I bought it. It was defiantly a very good deal as it improved the Transmission, Throttle and overall pep of the car. It only cost me one unlock on my Xcal2 as the new flash was viewed as a different vehicle by the Xcal2.