Random Misfires / Camshaft Position Sensor - Fixed!

exist3nce · Post by **exist3nce** » Tue Aug 15, 2006 2:20 pm

So I was driving with some friends 2 nights ago. You could call it "spirited" driving haaha. Anyways, I came around a corner hard and punched it in 1st gear, at about 4000rpm the engine sudenly lost alot of power and became very rough as well as making a very strange sound. It only lasted a couple of seconds, and then it was fine for the rest of the night. The next day I hooked up my laptop and OBDII cable to the car and tried starting it. It started but was idling VERY rough with lots of shaking and vibrating. Within a few seconds the check engine light started blinking. I read the code and it was P0300 - "P0300 Random/Multiple Cylinder Misfire Detected" which seems pretty serious. I proceded to check my spark plugs and cables and they all seemed ok. When I re connected everything it seemed to run fine.

I am worried that it may come back again

. What would cause this problem, and what else should I check for? Thanks!

car > 2004 Optra LS, 5spd Manual, U20SED

lanowoo · Post by **lanowoo** » Tue Aug 15, 2006 4:42 pm

electronic..like your coil could be bad

exist3nce · Post by **exist3nce** » Tue Aug 15, 2006 5:35 pm

lanowoo wrote:electronic..like your coil could be bad

well how would i check for that?

exist3nce · Post by **exist3nce** » Wed Aug 16, 2006 3:26 am

Well it happened again tonight while I was sitting at a stop light. I was just idling, then engine started shuddering and shaking real bad, but only for a couple of seconds, then all was fine. I am reluctant to take it to the dealer because of the mods I have installed (none of which should have caused a problem like this).

Please............ any more ideas on how to solve this problem?

JohnnyC · Post by **JohnnyC** » Wed Aug 16, 2006 4:17 am

It's possible you also have a flakey ignition wire, but that's doubtful considering that they were random misfires. You may have charred up your spark plugs as well. Pull your plugs and check them out to see if you've damaged them... (Race cars have to put new plugs in EVERY RACE from what I understand).

GsiTurbo · Post by **GsiTurbo** » Wed Aug 16, 2006 4:51 am

Could be related to the cam sensor, as these motors do like to have them installed.. or could be knock sensor or indeed, the coil. Have you reset the ECU yet?

MMamdouh · Post by **MMamdouh** » Wed Aug 16, 2006 9:04 am

was it a right hand corner?

can you make the car do that - the misfire - by tampring with the ignition wires and/or coil pack socket?

how old is your fuel filter, spark plugs, leds and coilpack?

MMamdouh

exist3nce · Post by **exist3nce** » Wed Aug 16, 2006 1:18 pm

JohnnyC wrote:It's possible you also have a flakey ignition wire, but that's doubtful considering that they were random misfires. You may have charred up your spark plugs as well. Pull your plugs and check them out to see if you've damaged them... (Race cars have to put new plugs in EVERY RACE from what I understand).

I already checked my plugs (first post), they were perfectly ok and no signs of damage to the wires either.

exist3nce · Post by **exist3nce** » Wed Aug 16, 2006 1:23 pm

GsiTurbo wrote:Could be related to the cam sensor, as these motors do like to have them installed.. or could be knock sensor or indeed, the coil. Have you reset the ECU yet?

What do you mean "these motors do like to have them installed"? How would I check/test the knock/cam sensor or coil? The ECU was reset about 4 days before this started happening to try to clear another check engine light that came on (this one I never got to scan, but it was not the same issue as this time because it was steady on instead of flashing, and there were NO driveability problems)

exist3nce · Post by **exist3nce** » Wed Aug 16, 2006 1:27 pm

MMamdouh wrote:was it a right hand corner?

can you make the car do that - the misfire - by tampring with the ignition wires and/or coil pack socket?

how old is your fuel filter, spark plugs, leds and coilpack?

MMamdouh

The corner when it first happened was a hard left, altho what difference would it make?

I can't seem to make the car do it by wiggling several wires around the engine bay, but I'm not sure if I'm trying the right ones.

Fuel filter is original OEM, About 42,000km on it.

MMamdouh · Post by **MMamdouh** » Thu Aug 17, 2006 10:33 am

exist3nce wrote:
The corner when it first happened was a hard left, altho what difference would it make?

a hard right hand corner can make fuel go to the farmost left side of the tank and cause momentarly fuel starvation... it can happen under very special sircumstances (spelling).

exist3nce wrote:I can't seem to make the car do it by wiggling several wires around the engine bay, but I'm not sure if I'm trying the right ones.

then your wiring is OK

exist3nce wrote:Fuel filter is original OEM, About 42,000km on it.

OMG

i am sure it is blocked as hell by now... under my countrey's "nice" conditions the fuel filter gets clogged after some 20,000 kms so under the best reconing yours is blocked indeed.

MMamdouh

exist3nce · Post by **exist3nce** » Thu Aug 17, 2006 3:15 pm

MMamdouh wrote:
exist3nce wrote:Fuel filter is original OEM, About 42,000km on it.
OMG i am sure it is blocked as hell by now... under my countrey's "nice" conditions the fuel filter gets clogged after some 20,000 kms so under the best reconing yours is blocked indeed.

MMamdouh

I don't think it says anything in the maintainance schedule about changing the fuel filter this early?

exist3nce · Post by **exist3nce** » Thu Aug 17, 2006 3:19 pm

Was driving around again last night while keeping the laptop hooked up to monitor things. The check engine light came on, but this time a steady one, not flashing. There were no chages in drivability. Scanned the code and got P0342 "Camshaft Position Sensor A Circuit Low Input (Bank 1)". Could this sensor be causing my misfiring problems?

kinkyllama · Post by **kinkyllama** » Thu Aug 17, 2006 6:54 pm

exist3nce wrote: Could this sensor be causing my misfiring problems?

Not sure the exact answer but I know when I've unplugged mine for testing it hesitates big time when you press the gas and wont go above something like 4k rpm and start blowing out black smoke like no other.

MMamdouh · Post by **MMamdouh** » Thu Aug 17, 2006 10:53 pm

exist3nce wrote:
MMamdouh wrote:
exist3nce wrote:Fuel filter is original OEM, About 42,000km on it.
OMG i am sure it is blocked as hell by now... under my countrey's "nice" conditions the fuel filter gets clogged after some 20,000 kms so under the best reconing yours is blocked indeed.

MMamdouh
I don't think it says anything in the maintainance schedule about changing the fuel filter this early?

i have it mentioned very clear in my user's manual, fuel filter @ 40,000 kms... at half this distance mine is subistantially restricted.

MMamdouh