P0300 Code
Thread Starter
8th Gear
Joined: Sep 2003
Posts: 8
Likes: 0
From: Allentown PA
P0300 Code
I have a 96 LT4 Coupe Classic Edition with 59,000 mile. The only work I have had to do on the car was replace the emissions check valves based upon codes P1416 (two years ago) and yesterday P1415 for the passanger then drivers side. Then in Sept 2003 replaced the water pump as it was leaking (opti spark problems never came into play as far as i could tell with the leak). I am embarassed to say my car started running bad about two months ago and I did not do anything as it did not seem serious and alot of other issues at that time (nothing to do with the car). About 3 to 4 months ago the car started to sputter on occasion when in high gear (5th or 6th) and giving it a lot of throttle including WOT. Then it got worse with in the last 2 months to happening in any gear when giving a lot of throttle over 2000 to 2500 rpm. Now it runs terrible all the time, sputtering all the time and rough idle all the time. In the beggining I thought it might be an O2 sensor because the car ran better when cold or maybe a fuel delivery issue. But now it is terrible all the time and I am showing a P0300 code for Random Multiple Cylinder Misfire. I got this scanned as before from the local auto store.
Tonight I will check the spark plug wires as best I can. I was also thinking about changing the fuel filter. Can clogged fuel injectors cause this as well? Are these symptoms of bad O2 sensors?
Any advise is welcomed. Forgive my lack of action early in the problem.
Tonight I will check the spark plug wires as best I can. I was also thinking about changing the fuel filter. Can clogged fuel injectors cause this as well? Are these symptoms of bad O2 sensors?
Any advise is welcomed. Forgive my lack of action early in the problem.
Team Owner
Joined: Aug 2000
Posts: 40,156
Likes: 45
From: San Pedro CA
you really need to invest in a Helms manual... that will help you decode and troubleshoot these problems. www.helminc.com
Instructor
Joined: Jun 2003
Posts: 101
Likes: 0
From: Austin TX
my experiece with the P300 random misfire code relates to swapping the stock lt4 cam for the gm hot cam. a couple months later it threw this code. i subsequently bought lt1 edit and had a local shop tune it. it is my understanding that the computer samples for misfire from intitial idle (800 rpm). the recommended remediation from this forum is to edit the pcm so that it does not check for misfire until 1500 rpm. however, the shop i chose decided to have it not check at all and the light and code disappeared.
