Random Misfire...Awesome...
06-09-2013, 08:14 PM
#1
Random Misfire...Awesome... Well driving along today and as I take off from a stop light my car decides to develop a random misfire. The best kind, not just a certain cylinder, nope just my luck, random.
So I will begin to do minimal testing whilst throwing parts at it.
Starting with unplugging the MAF, then onto plugs and wires, then fuel filter, then drain tank, cam, crank sensor, test coils, and lastly injectors.
Hopefully the problem will be a lot cheaper and easier to solve than that list.
Any advice for my new found predicament?
So I will begin to do minimal testing whilst throwing parts at it.
Starting with unplugging the MAF, then onto plugs and wires, then fuel filter, then drain tank, cam, crank sensor, test coils, and lastly injectors.
Hopefully the problem will be a lot cheaper and easier to solve than that list.
Any advice for my new found predicament?
06-09-2013, 08:27 PM
#2
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How did you eliminate the possibility of it being just one cylinder? I had a slight misfire that only occurred at certain loads, etc that I barely noticed it until it started getting worse. Turned out to be a loose plug wire that I couldn't get to properly seat on the plug. New wires and problem solved. So yeah, probably a good order of things to check that you have.
06-09-2013, 08:35 PM
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I had the same random misfire code. I forgot to mention that. Turned out it was a specific cylinder though. Not sure why the computer couldn't tell that.
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06-09-2013, 09:31 PM
#9
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The P0300 is the only DTC there is now. GM used to have a DTC for every cylinder (P0301 - P0308) to identify exactly what cylinder was misfiring. Apparently that was too useful and they have not done that since before 2000. The computer calculates whether the engine is misfiring by the rotation speed on a power stroke as read by the crank sensor.
Can you feel the miss? When does it occur? Does it get better or worse with a load (lugging the engine)? Does it get better or worse when cold/hot? This will define what type of miss you have to narrow it down.
If you have a bidirectional scan tool, you can do a cylinder balance test.
Can you feel the miss? When does it occur? Does it get better or worse with a load (lugging the engine)? Does it get better or worse when cold/hot? This will define what type of miss you have to narrow it down.
If you have a bidirectional scan tool, you can do a cylinder balance test.
06-09-2013, 10:15 PM
#12
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I get the individual cylinder miss fire codes on hptuners. If someone local to you has that or efi live or hell even a tech2 you would be able to possibly narrow down your search. The individual cylinder codes can stay hidden as annum mature code and not come up with some software.
06-09-2013, 10:52 PM
#13
TECH Fanatic
I get the individual cylinder miss fire codes on hptuners. If someone local to you has that or efi live or hell even a tech2 you would be able to possibly narrow down your search. The individual cylinder codes can stay hidden as annum mature code and not come up with some software.
06-10-2013, 10:58 AM
#16
This is what I worry most about. Because it is no easy task draining the tank to replace it. Plus it it is indeed bad gas it would have to be just terrible gas (alot of water). I filled up at a place I do regularly (not ever time, but often enough) on saturday afternoon (car was empty!) then drove approx 30 miles on sat. Sunday morning I made it 2 miles before it started skipping badly.
So if it is indeed bad gas that sucks, because I'm going to start throwing parts at it first (plugs wires) and test other things first before I get into draining the tank. Which possibly makes all the previous work for not. Thus my predicament. But, I will be throwing quality parts at it so in a sens I can justify it as upgrading!
Also, If I could use a scan tool for free and either myself or its owner looked at it awesome. But if it is going to cost me 100$ then I feel that 100$ maybe better spent else where. The whole random misfire is a catch 22 really.
So if it is indeed bad gas that sucks, because I'm going to start throwing parts at it first (plugs wires) and test other things first before I get into draining the tank. Which possibly makes all the previous work for not. Thus my predicament. But, I will be throwing quality parts at it so in a sens I can justify it as upgrading!
Also, If I could use a scan tool for free and either myself or its owner looked at it awesome. But if it is going to cost me 100$ then I feel that 100$ maybe better spent else where. The whole random misfire is a catch 22 really.
06-10-2013, 07:23 PM
#19
I think your stressing out to early.......
You need a scan tool to find out what cylinders are misfiring before you go any further ....
That will give you a place to start..,
Misfire is not a superbig deal ... I also have a tech2 and have worked at the gm dealer for the last 15 years...
You need a scan tool to find out what cylinders are misfiring before you go any further ....
That will give you a place to start..,
Misfire is not a superbig deal ... I also have a tech2 and have worked at the gm dealer for the last 15 years...
