misfire under light load
02-27-2014, 10:57 AM
#1
misfire under light load
It seems like this is a popular topic recently and I find myself having the same problem. It started out very intermittent and has developed into a regular issue. Most often happens while in overdruve and trying to slowly accelerate. The truck starts to stumble dramatically. It stops if I turn overdrive off or accelerate more causing the truck to downshift.
I started with easy/cheapest things first. Changed air filter and fuel filter hoping to get lucky but the problem is still there. I am now in tge process of swapping out COPs one at a time with a new one hopibg that may be the problem.
Started with cylinder 1 and noticed improvement but the misfire was still there. Went to second and it was as bad as it was before. Going to keep going until hopefully I find the bad one. I will say that while changing out 1 and 2 I noticed that both plug wells looked wet and smelled faintly of raw fuel. I tried tightening thinking that maybe they had worked themselves out a little but there wasn't any movement as well as no real imorovement as far as the miss.
The truck has 155k on it and the plugs were changed roughly 40k miles ago. I have no codes being thrown so I do not have a specific cylinder/cylinders to look at. From what I've read on here and the net this can be a timely process to figure out and sometimes a costly one. Ive got the time but not the finances to change all the plugs and COPs.
Im hoping maybe someone may have another idea of something to try aside from taking it to a shop or replacing everything on every cylinder. Injectors are next on my list to start changing if it doesn't get better.
I started with easy/cheapest things first. Changed air filter and fuel filter hoping to get lucky but the problem is still there. I am now in tge process of swapping out COPs one at a time with a new one hopibg that may be the problem.
Started with cylinder 1 and noticed improvement but the misfire was still there. Went to second and it was as bad as it was before. Going to keep going until hopefully I find the bad one. I will say that while changing out 1 and 2 I noticed that both plug wells looked wet and smelled faintly of raw fuel. I tried tightening thinking that maybe they had worked themselves out a little but there wasn't any movement as well as no real imorovement as far as the miss.
The truck has 155k on it and the plugs were changed roughly 40k miles ago. I have no codes being thrown so I do not have a specific cylinder/cylinders to look at. From what I've read on here and the net this can be a timely process to figure out and sometimes a costly one. Ive got the time but not the finances to change all the plugs and COPs.
Im hoping maybe someone may have another idea of something to try aside from taking it to a shop or replacing everything on every cylinder. Injectors are next on my list to start changing if it doesn't get better.
02-27-2014, 11:29 AM
#2
Mark
iTrader: (1)
I would also check the condition of your FPDM located under your spare tire normally corroded to the frame rail..
02-27-2014, 12:06 PM
#3
I had the same exact issue after just changing my plugs last week. Hooked up the computer at the shop and it was misfiring on #6. Took that plug out and it had chipped a piece of the metal housing off the lower part of the plug and the electrode was completely gone. Put a new plug in and still had the issue. Ended up muscling the plug down a little tighter and the issue has gone away. That plug was tightening down harder than all of the others and the only thing we could figure out was that it was not getting properly seated all the way down into the block. Just have to be careful that you don't crack them by getting them too tight.