Results 1 to 17 of 17
Thread: HELP!! Missfire
-
02-12-2008, 05:54 PM #1
HELP!! Missfire
Ok guys, my car has been missfiring for the past 2 weeks and has not stopped. It P0300 i think, its def a random missfire. I just dont know what the fuck it is and its driving me nuts driving it!! I checked everything and its all good. Plugs, wires, coilpacks. I had a few friends come check her out to and still nothing. I had my mechanic look at it, and he said when he drove it, it rain fine, and it did for a few hours. The only thing i can think off is a sensor maybe?? My water pump is leaking a bit and im getting that fixed first thing tommorow at 6am (since i will be at college, i told my mechanic to swap it out) Maybe coolant got onto a sensor or wire and thats wuts causing it?? I also made a thread a few weeks back regarding a bad cat, but it turns out the previous owner gutted one out, and thats the one that is throwing off codes. Its hallow and theres nothing in it. So maybe a little coolant got into something it wasnt suppose to and thats whats causing it, or could it be the dam cat?? Any1??
-
02-12-2008, 06:01 PM #2
how many miles and mods? fuel injectors will cause a misfire as well. myabe look into cleaning them
-
02-12-2008, 07:00 PM #3
how many miles on the fuel filter also?
-
02-13-2008, 08:48 AM #4
The cars has a lil over 95k miles. I didnt touch the injectors, but maybe the previouis owner might have, never checked it out. Yeah, i think i might need a new fuel filter as well. Any brand in perticular? Is it worth changing injectors?? If so, i most likley will get some SVO's.
-
02-13-2008, 10:50 AM #5
well, I wouldn't just run out and buy injectors on a hunch. I just use any parts store fuel filter, I'm not picky about that stuff though. You could try changing out the fuel filter and running some injector cleaner through the car and see if that helps you any. Cheap and easy thing to rule out.
any mods on the car?
-
02-13-2008, 02:45 PM #6
Mostly stock....SLP lid and exhaust w/3" cutout, NGK plugs, MSD wires. Those are the only things that i can think of that might have anything to do with it. I ran injector cleaner a while back but i dont know how often i should do it. Defenatley gonna try and and swap the fuel filter. I just put in a new water pump, and it seemed to run fine for like 5 min then it went back to doing the same thing. U think it could prehaps be the cat code thats throwing it off. My cat is gutted, so my SES light came on, but in reality there is nothing wrong with the cat.
-
02-13-2008, 03:03 PM #7
- Join Date
- Jul 2005
- Location
- Jacksonville, FL
- Posts
- 2,723
I'd visit gearchatter.com for your year and look up P0300 for the misfire and P0420/P0430 for the post cat code to get some ideas. Something else you can try is start/rev the car in the dark and look for any arcing around the coils/plugs/wires, etc.
-
02-13-2008, 03:12 PM #8
-
02-13-2008, 03:56 PM #9
- Join Date
- Jul 2005
- Location
- Jacksonville, FL
- Posts
- 2,723
You don't need to log on to see the DTC codes/descriptions/diagnostics. Just go to www.gearchatter.com/ and click on 1998 F-Body DTC, click on the codes.
-
02-19-2008, 02:12 PM #10
- Join Date
- Feb 2008
- Location
- California
- Posts
- 1
Black- 1998 Trans-Am
I had a random missfire on mine which turned out to be the crank position sensor (CPS). (Located behind the starter)
After the shop replaced it it still missfired.
Turns out that the sensor has to be synchronized with the crank for the missfire to go away. Not just replace and go.
They said the mechanics at the local GM dealer just found out about this issue a couple years ago. They had never had to sync a CPS before.
-
02-19-2008, 03:27 PM #11
I was flipping though my service manula for the 2000 year F-bodies and stumbled across that the EGR valve can set off a misfire code as well.
-
02-19-2008, 04:41 PM #12
-
02-19-2008, 06:13 PM #13
Yea, if the EGR valve is not operating porprerly it can cause the p0300 code for some reason *shrugs*. Right from p 6-1964
Too much EGR flow causes any of the following conditions to occur:
The engine stalls after a cold start
The engine stalls during closed throttle conditions
The vehicle surges during a cruise condition
A rough Idle
ADTC P0300
-
03-22-2008, 12:36 PM #14
-
03-23-2008, 09:48 AM #15
The quick fix would be to take it off and carefully clean the carbon out of it. Other wise look at replacing it in its entiity. I am not sure what parts ofteh valve its self can be reaplced, but that is where I would start.
-
03-24-2008, 04:52 AM #16
The "Misfire code" will trip the dreaded P1336 code which is the CPS, you need a tech II or EFI live to run the sync. You set the tech II on CPS relearn, with the vehicle in park, you raise the idle to 4K until the engine starts to stumble, you let off the gas, and during deacceleration it relearns the sync. YOU DO THIS AFTER YOU HAVE SOLVED THE P0300 PROBLEM.
SteveC
-
03-24-2008, 05:50 AM #17
Thread Information
Users Browsing this Thread
There are currently 1 users browsing this thread. (0 members and 1 guests)
Similar Threads
-
Help: Cylinder 8 Missfire
By davidz28 in forum General HelpReplies: 10Last Post: 08-26-2011, 09:37 AM -
missfire on cylinder 6
By lsmaxxed in forum General HelpReplies: 44Last Post: 06-30-2011, 01:57 PM -
Help!!! Missfire
By tcondra in forum General HelpReplies: 5Last Post: 07-26-2009, 09:08 PM -
Help: LT1 Pinging/ Missfire
By WhiteThunderZ28 in forum LT1Replies: 0Last Post: 04-19-2008, 08:03 PM -
help having problems car missfire
By william SS in forum Internal EngineReplies: 5Last Post: 06-10-2007, 10:20 AM
Bookmarks