My truck has been misfiring and pinging so i asked a few techs at work and they all said more than likly a plenum gasket. So today I replaced my plenum gasket and intake manifold gaskets and the damn thing still misfires. What a waste of a day and $60 bucks in parts. The truck only misfires in 4th gear, vaccuming at about 5-0 (WOT)

 

Could also be cracked heads, blown head gasket, bad wires.

Have you done the wire re-route per the TSB?

Whats he plug look like?

 

the plugs are fine, but when ever i change them, Cylinder 8 always seems to be darker than the rest and thats where i have the misfire. I'm going to get different spark plug wires, I have Taylor Performance ones in there now but I dont need them and that might fix the misfire, who knows.

 

well i fix'd the problem. lol. I did the TSB on spark plug wire re-route. No more misfire, no more codes. I still done have all power in 4th gear and it still decreases speed when climbing hills in 4th gear. but im just happy no more misfiring and hearing that annoying pinging. Thanks for the Help Guys!

 

Where is that TSB located? Thx

 

http://dodgeram.info/tsb/1998/18-48-98/18-48-98-v8.htm

 

I picked up my '96 with CEL illuminated and the Cyl8 then 1-7 all misfiring. Previous owner did not pay any attention to the condition of the plugs and had tossed in a cheap set of wires. Even after trying to route them per the TSB, problem would always appear within 10miles of driving after fixing and clearing the code. I got cheesed off and went to AutoZone. Bought 1-set new Bosch premium wires w/split loom on there, qty-8 Denso copper plugs 1 heat-range colder than stock (fitment is '95 Dodge Stealth TwinTurbo). Brought it all home and spent half and hour gapping the plugs exactly as I could. Then proceeded to swap everything back out.

Having worked on motors always w/alloy heads it was sort of wierd torquing the spark-plugs to 30ft/lbs (read: seriously tight...), but I did not bother to clock the electrodes. After swapping all plugs I found that Cyl-8's old mis-matched plug was not firing at all and completely oil-fouled. So on went the new wires following the TSB exactly. My coil was pretty new having replaced that the previous weekend, cap and rotor same... At same time I changed out for 5qts of 10w30 and a new filter. Pulled the coil-wire and cranked motor a few times to set base oil-pressure. Re-attached coil and fired her up.

Oooohhhhhh. So 8cyls really makes a Bbbbbiiiigggggg difference. Engine idled smoother and after everything checked out - ran w/gobs more power. Tired old truck and motor. Not sure if Cyl8 will foul out again, but whoa-mamma what a different beast. 100mile test loop with the OBD-II scan tool and narry a code/DTC set.

So if you're chasing this misfire and CEL, replace the entire ignition side w/good quality stuff and follow the TSB exactly. Odds are if you've good compression in that bore that it will indeed go away. I probably spent 2hrs fussing over plug wire routing and the specifics of the TSB and frankly it was probably worth it.

Good luck!

 

Im going to to this...

Ever since ive got my truck, if I get onto the highway really slow it will shift into od with the tc locked at around 40 and around 45 I would always get a surgeing... worse at times less at times...

Ive never had any problems with low power at highway speeds though, im in michigan which is really hilly and mine powers up the hills with out even breaking a sweat... I have to give it a little bit more gas when im pulling a trailer, but thats expected.

Its nice to know what my surgeing is, i replaced the wires just becasue I could feel it was that type of a problem it helps but dident fix it.

 

Josh - having grown up in Michigan myself (lower P, but mid and Northern) - I just gotta ask where is this "really hilly" section of the state? Granted Michigan has gobs more elevation changes than Houston, TX (can you say pankcake...), but thinking of Michigan as having something like the canyon run from Boulder, CO into the mountains made me chuckle....

Since you replaced the wires did you follow the TSB exactly? - if not go back and re-do them. It doesn't sound like you're getting a check-engine light code but rather the stuff about the TPS signal being out of profile with the actual throttle opening. I noticed on my truck the TPS reads 15% absolute open when the machine is at temp and idling with a stretched out throttle cable. I've not yet cleaned it up to see if I can get closer to 5% or less with the butterflies closed.

Good luck in chasing your issue...

 

Yea i'm not too worried about not having all the power in 4th gear. I'm just so happy that i finally tracked down the misfire in cylinder 8. I'm going to look into a new TPS and i bet that will clear it up or help it out.