I have an 02 Ram 5.9 and am having an odd situation and would like some help. Every time during or after it rains the truck will buck and surge. I have noticed it does it around the 50-60mph range at low rpm while under a load. I've tried one time during this problem to give it gas and make it down shift and the rpm went way up the SES light flashed a couple times then quit. Then the light went off completely and the truck returned back to normal driving.

Keep in mind this is all within a 15 min drive home from work. I tried reading the codes and there were none. It had rained last night and the truck did it again on the way to work, about halfway there the trucks driving returned completely to normal with no problems. This is really starting to bug me, what do you guys think the problem could be?

 

It's gonna be a wire or coil pack issue. Whichever cylinder it is, I'd look at that wire and coil real closely, probably find it cracked, letting water in. Furd 5.4L engines are notorious for cylinder 4 misfires as the A/C drain was right above the coil pack and the drip would eventually short it out, causing a misfire...

 

I cant figure out which cylinder it is b/c its not throwing a code in OBD2, every time i have the problem anymore the SES light isnt even coming on, I still try looking up a code and nothing shows up. I do have a new set of plugs and wires to put in though. Is there anything specific to these trucks(like the ford) that are known to have a specific coil get water to it? Also there is no coil on an 02 5.9L its a distributor.

 

None that I'm aware of, I had a 5.9 in my '98 RCSB 1500 4x4. Woulda figured they'da gone to coil packs by '02, but I guess not with them axing the engine.
If the wires are new, you try looking at the distributor cap? Boy, I miss the days of reaching under the hood and getting bit by a cracked distributor cap.

Without a code, are you even sure it's due to a misfire?

 

adding a thought...
MIL does flash ? How are you reading codes ...Try Using a scanner- ck history and pending codes as well as higher # maybe a clue

 

No im not, thats just the best way i can describe it, it will buck and surge but its not trans. related either. So misfire was the only thing I could think of. I have not checked the dist. yet, I know i need to get the plugs and wires changed just havent had time with my work schedule. I have a friend that works at advanced and he had 3 other people come in with the same truck when we had a bad storm with the exact same problem but they didnt know what it was either.

To say the least im not one to leave problems with my vehicles, I like to fix it but this one is irritating b/c i cant pin point what it is lol, I'm sure u know how that goes though.

 

No it only flashed one time, the time i tried accelerating and the rpm climbed then i let out of it. About 5 mins later the light went away and the truck drove normal. I use an obd2 scanner to read the codes and there wasnt any codes to locate. I had the MIL light flash once because the damn gas cap wasnt tight enough!

 

I agree with Hammer, If you have plugs and wires to change then I would go ahead and change them and while your at it change the distributor cap and all while your in there just to eliminate all that. Good luck!

 

I have a 2003 5.9 and have the same problem.These trucks do have a coil that goes to the distributer which is mounted facing the front of the engine on the left side on the face of the block.I just figured it had a fine hair line crack in it that lets moisture in when its wet.

 

Spray a can of silicone all over the engine while it's running.(plug wires & coil packs) This will isolate your problem. Your engine will surge once an open break or crack is found. It will make a mess, but once the problem is fixed, you can pressure wash everything clean(while your engine is running and stay off the alternator while sprayingwith water)