2001 dodge ram 1500 5.9l- slight misfire

[ramlife59]

about 2 months ago i started noticing a slight jerk/buck while i was driving my truck. since i first noticed the issue occurring, it has very rarely happened since. it only ever happens when im driving on the highway and its really only when im cruising. im not accelerating, going up hill, or anything like that.... just cruising. i did an DYI stress test on the engine to see if it was maybe a spark plug (i am not a mechanic, dont claim to be... just find out how to fix things on my own) but the engine seems to be running strong with no jerks or anything. it wasnt until recently that i went to start my truck up one morning and it started up rough.... which it has never done before. but it ran fine after that. dont know if that has anything to do with my original problem. im not getting any kind of CEL pop up either. anybody got any advice?

 

[19Ram150098]

The Jerking/Bucking could be a sign of the torque converter failing to lock up.. just a thought..

 

[ramlife59]

Thanks haven’t had that mentioned to me so I will look into that

 

[SportRam00]

Check your TPS! I had a similar issue where the truck would be cruising and the rpms would jump 100-200 above my cruising speed at random. TPS fixed the problem and a a fairly common item to replace.

 

[ramlife59]

Thanks for the input sportsram00, I will do some research on it.

Just to update, I took my truck to autozone and asked them to scan for any codes that were stored and low and behold I had one for a small evap leak! I’m not sold on the idea that this could be my misfiring symptom issues but I’m still going to fix the leak. I’ve had that code before (2 years ago..) accompanied with the large evap leak code and did a lot of new hoses above charcoal canister and it solved that problem.
So, could a small evap leak somewhere in the system cause a slight jerk in the engine while driving? Still having the issue but only like once every time I drive home from work, never in the morning.

 

[Nick_rp]

Could probably just use a tune up. Clean the common build up areas like egr, tb, iac etc, replace the wear and tear items like plugs wires. Check the spray pattern of the injectors. All the good stuff. It is almost 20 years old.

 

[SportRam00]

Definitely fix the EVAP leak as that would cause a similar misfire issue.

 

[ramlife59]

so, just in case anybody out there has a similar issue to mine, the issue was the ignition coil. i took the advice from several people and just started working on getting what i needed for tuning it up and before i had started i got a lead from somewhere that high heat and humidity could affect an ignition coil more so than other parts so i replaced it first. drove it for 2 days, and my issue had disappeared! needless to say i finished the tune up and did have some buildup on 2 spark plugs, one spot on my distributor cap, and my rotor seemed worn so it was over due. but i have not had the misfire issue once since replacing my coil and it was getting pretty consistent there in the afternoons towards the end.

 

[SportRam00]

Heat and moisture are the devil with ignition parts. Glad you figured it out and posted your solution.

 

[ramlife59]

Thanks for everyones input and suggestions.

Anybody know how to find/fix a vacuum leak? My air seems to go out or gets sucked somewhere else every once in a while when accelerating. As soon as I let off the gas it comes back and within seconds I hear a slight hollow pop under dash/hood area which I’m assuming is a blend door.

 

[SportRam00]

Check the vacuum lines on the side of the intake manifold for cracks and leaks. Also check the cruise control vacuum lines as well as I think they are all connected. A simple tick I learned is, buy a cheap cigar. Take a puff off of it and blow into the lines at various places. If you see smoke, you found the leak.

 

[ramlife59]

thanks, ill be giving that a shot this weekend. gives me a good reason to buy some cigars too

 

[Mop]

If you find cracks in your vacuum lines, 3mm rubber tubing replaces the plastic lines, and does the trick.