97lt1z28

iTrader: (1)

guys i am goin crazy here please help. its a 98 ls1 camaro 6 speed with about 45K on it. Car skipts and sputter and eventually throws a po300. so far i have changed
fuel filter
entire mass air flow
plugs
wires
fuel filter
checked fuel pump (got 60 pounds)
checked vacum (got 20 pounds)
Checked IAC...good
Checked all of my fuses
Ran proane around the motor to check for other vacum leaks
listened to injectors...sound good.

What the hell else could this be? I am pullin my hair out over here!!please halp.

blade2222

O2 sensors can do this, it happened to me got a misfire code but not one for a o2. Was reading lean and PCM was dumping so much fuel in it would misfire.

O2Form

Check the intake bolts...mine did the same thing and they were loose.

97lt1z28

iTrader: (1)

i qill chwck both of these things tommrorow. the car has long tubes so i will only have to check two o2's. How do i check to see if these are working?i will check the intake bolts as well. what are the chances of it being a pcv and egr valve?

97lt1z28

iTrader: (1)

bump...how can i check my o2's

EVERETTDREW

iTrader: (2)

Keep this thread updated my car is doing something similar.

WS6 Rampage

iTrader: (3)

If you have an OHM meter & and a torch you can test them like this.
http://www.youtube.com/watch?v=vdn4D...e_gdata_player

P0300 is a 'detected' misfire typically caused by spark plugs fouling out! ...
If it was your o2s, in conjunction with P0300, you'd also run a P0420 Bank 1 (drivers side o2) and or P0430, Bank 2 (passenger side o2)... If your running lean and o2s are bad, a sign would be if they're "chalk" white.

97lt1z28

iTrader: (1)

thanks rampage...i i am not throwing any other codes and i pulled all my plugs and wires and they are looking great. I feel like i have checked and changed every possible thing excepts for my o2's, my coil packs, and i havent pulled a valve cover to check for a broekn valve spring. I literally have done every other thing that i have found in the threads on this and other websites.

2002 Trans Am

monitoring this thread

COSTIGAN86

iTrader: (8)

With a Tech2 you can monitor live misfires and determine what cylinder(s) is misfiring. If it is only one cylinder, you can then narrow it down further. Doing an injector balance test will tell if there is a leaking or restricted injector. You didn't mention what rpms this occurs at. Is it a dead skip, under a load, or at idle? You may also want to do a cylinder leakdown test to check for a burnt or leaking valve.

live2dew

iTrader: (3)

+1 for removing valve covers. check springs.

happened to me. look at them close. lucky for the beehive shape, it collapsed on itself and didnt ruin the motor. i put about 80 miles on it with the broken spring without any damage. p300 code, it was a mess to drive and track down. covers come off in a few minutes. good luck

Silver Bullet 8150

iTrader: (1)

I have a car that has the same code p0300 and cylinder 1,3,5,7 (driver side bank) are going crazy on the scantool. now if it was an a/f sensor why wouldnt i get a sensor code instead of misfire codes??

2002 Trans Am

Update

Found the issue, it was my rigged O2 extensions. I unplugged both and the car is running perfect aside from throwing the O2 codes

Ordering new O2 extensions and some heat sleeves so I can protect the **** out of those O2 extensions

2002 Trans Am

Anyone know what size heat sleeve will get over the O2 connectors? I'm thinking 1" should be good?

97lt1z28

iTrader: (1)

well i have officially tried every thing except for pulling a valve covers to check for a broken valvespring and replacing my coil packs (expensive) hopefully its one of these. It sucks new coil packs are so much money. anyone know where to get a set of them for cheap?

FiredUpZ28

Just an FYI you can't splice 02 sensor wires.... just to put it out there...

97lt1z28

iTrader: (1)

just a update....after changing everything...any i do mean everything else i changed my o2 sensors and the car has been runing great. I dont want to jinx anything but the last couple rides in it have been incident free and its running like a champ. I just hope it stays this way. The old o2's had so much build up on them and looked really bad. I am going to end up sending my ECU out to pcmforless and getting a tune on the car. i feel it will be a couple hundred bucks well spent. Thanks for any help.

FiredUpZ28

I dunno if I would do a mail-order tune with a heads/cam car - you might be better off getting a dyno tune.