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Car Problems? NG900 or old 9-3 Only If you're experiencing problems with your NG900 or 9-3, post your question in here. CEL Code or GTFO!

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Old 02-07-2006, 12:12 PM   #1
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Random Misfire.

Ok so Back in the summer I had what felt like a clogged injector, becasue evey so often it would feel like it was missing, but would then keep on going just fine...this was at any RPM under any load...completely random and if never through a code, and the misses were very minor. I ran a bottle of Techron Through it and after that tank of gas everything was all set.

I also had it mis becasue of a DI it through a code as well as the CEL blinking becasue CAT damage could occur (I am catless at the moment so its ok), and so I replaced the DI at the end of june and all was good.

Well now here we are in Feburary and a few days ago it starts missing again just like it did in the early summer, but no code yet...so I think ok as soon as this tank of gas is down I'll throw in another bottle of Techron and hope for the best. Well now a few days later its getting a lot worse...it threw a Random misfire code P0300, which worries me that its not clogged injectors. It happens at any load value and RPM value any speed. Sometimes I will go for a drive and it wont happen at all and sometimes it will happen a little bit, others its horrible and starts falshing the CEl at me.

The DI is around 7 months old, the spark plugs are like 6000 miles old I haavent checked them yet, but I will regap and also Di electric grease them.

Any other suggestions?

Fuel filter is about 26k miles old
Could it be a fuel pump relay flaking out?? (car always starts)
a FPR?
A shitty tank of gas?

the only difference I have done in my driving style is tried to cut back a little on my aggressiveness and drive more like a normal person to get some better milage out of it.

A week before the problem started the car did sit for a week, but I dunno.

I have about 3/8ths a tank of gas left, so I am going to still run the techron through and hope for the best.

Burns if you see this do you think you could get me the diagnostic flow charts for codes...

P0300
P0132
P0138

Those 2 other codes are o2 codes stating sensor voltage high...the 138 is probabaly cause the rear o2 sensor is reading to much becasue of the lack of cat (it is spaced out of the pipe...but who knows)

but the front one...I mean does it say I am running rich....I do have my Dyno chart at home, thats showing I am fairly rich...but our cars tend to run pretty rich
Car 1999 9-3s T5
MODS are 3 inch DP
MBC+A and MP intercooler
GenSaab Intake
along with throttle body coolant bypass and phenolic spacer plate as far as the speed mods go

Im usually pretty good at figuring this shit out, but im drawing a blank on this shit.

Anyway to other people this is how a problem question should be asked....

any help is apreciated...at least the major jeep project is ggetting completed tonight after I get home from work, so I can drive that.


EDIT: What a great 1000th post huh?
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Old 02-07-2006, 12:44 PM   #2
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Gotta love random misfires, huh?

New plugs, new BPC, new airfilter, new DI, and resetting the ecu took care of that for me. Crappy, I know. Check your BPC, give it a cleaning - couldn't hurt, right?

Do you think you're running very rich all the time? What is your long term fuel trim? This was something that was waaaay off in my car before I had all the aforementioned parts replaced, might have contributed to the misfire code. Now someone with a Tech II?
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Old 02-07-2006, 12:51 PM   #3
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I had random misfires and it was a bad DI or so the dealer says.
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Old 02-07-2006, 12:57 PM   #4
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i have a MBC+A so the BPC should have nothing to do with it. DI is only 7 months old, so that shouldnt be shot...but who knows...they have warranties right?

I have a digimoto scan tool I can check the long term fuel trim
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Old 02-07-2006, 01:01 PM   #5
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Long term fuel trim should be no lower than -10. To you give you an idea how far mine was off, I was at -32. The mechanic told me that closer to -5 would be better.

Take the MBC off and see what the BPC does for you after an ECU reset.
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Old 02-07-2006, 01:02 PM   #6
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eww stock boost LOL...I dont know what that would do...myabe a ECU reset, but I think something else is causing the problem...I'll check long term fuel trim tongnight...or rather in the next hour or so after I get back from work
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Old 02-07-2006, 01:59 PM   #7
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hey josh, i feel you man. Let me know if you need anything
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Old 02-08-2006, 05:40 AM   #8
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Anyone?????

There is one other potentil thing I can think of...the car did sit for a week before this started....and this past saturday I was filling up wiht washer fluid in the autozone parking lot, and noticed mouse shit in the DI cassette indent....Maybe a wire got chewed or something
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Old 02-08-2006, 07:17 AM   #9
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Quote:
A week before the problem started the car did sit for a week, but I dunno.

I have about 3/8ths a tank of gas left, so I am going to still run the techron through and hope for the best.
With all the drastic changes in temperature here in the NE area the past few weeks you could have some water in your gas as a result of condensation (it was nearly 60 this past Friday, now mid 20s here in upstate NY). Water definitely doesn't burn and that could possibly be the cause of your problem. Try a full tank of gas and see if that helps at all.
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Old 02-08-2006, 08:29 AM   #10
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Yea that has crossed my mind too...thats why I figured I'd let this tank go as far as I can, then dump the thing of techron through and see what happens

good idea?
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