1994 Dakota missing

[mmeyer]

Hey All, I just bought a 94 Dakota 3.9L with 104000 miles. It was running pretty decent but needed a little tuneup so I put in plugs, wires, cap and rotor.It seemed to be running good when I" first did the tuneup but now it's missing quite a bit. It is missing more under load especially. I double checked all of the wires and plugs and everything seems to be good to go. Any ideas? There is no engine light coming on. It runs the same whether warm or cold. I'm thinking coil or fuel filter but I don't want to start throwing parts at it on a whim. Is the fuel filter in the tank? He just replaced the pump last year.

Thanks for any help in advance!

Mike

[Jeremy airjer W]

Where did you get the parts and what plugs did you install?

[efgh]

Did you reroute the plug wires the same way the original wires were? Wires wound around each other, I found are a no no. If you used parts that were bought at some discount stores, like airjet said, that could be your problem.

[mmeyer]

Thanks for the replies guys. I bought Champion Platinum plugs from Walmart but I bought the wires, cap and rotor at Forbes Bumper to Bumper. I did route the wires the same way using the wire looms that were there. Hope this helps.

Thanks

Mike

[delcecchi]

If I were to guess, and I am, I would surmise that you didn't get something connected firmly enough. You may have thought the connector was pushed onto the plug or into the coil, but it wasn't really.

That is what I would check first.

[Jeremy airjer W]

I don't think that engine calls for platinums but it also shouldn't hurt. I agree with the above. Check all the wire connections. Look for carbon tracking or corrosion caused by improper contacted. Check the plugs for cracked porcelain. I have run into more than one of these where the insulator for the center electrode will be bad and the spark will jump before it reaches the gap. You will see a definite black spot on the center insulator if this is the case.

[jmd1]

antiseize and dielectric grease in the boots to keep the plugs from locking into the head and boots from getting water in them. good luck

[Jeremy airjer W]

If the threads of the plugs are silver than they are Nickle plated and do not require any anti-seize. If you feel it is necessary than user sparingly.

If the threads of th plugs are black than deffinetly use a little anti-sieze.

Di-electric grease in the boots is always a good idea.

[mmeyer]

Ok guys, thanks for the advice. Based on that I pulled all of the plugs, they all looked good, electrodes all looked similar. Then I pulled the wires, cap and rotor and they all looked good as well. I double checked the firing order and reinstalled everything using dielectric on the boots. I checked for spark at each plug and they are all firing when idling. It idles fine and when I'm parked and rev the engine it doesn't seem to miss at all. When I'm driving and step on it then it misses. It seems ok when I'm at a steady speed but misses only when I accelerate.

Any more thoughts before I bring it to the shop?

Thanks again!

[delcecchi]

Ok guys, thanks for the advice. Based on that I pulled all of the plugs, they all looked good, electrodes all looked similar. Then I pulled the wires, cap and rotor and they all looked good as well. I double checked the firing order and reinstalled everything using dielectric on the boots. I checked for spark at each plug and they are all firing when idling. It idles fine and when I'm parked and rev the engine it doesn't seem to miss at all. When I'm driving and step on it then it misses. It seems ok when I'm at a steady speed but misses only when I accelerate.

Any more thoughts before I bring it to the shop?

Thanks again!

I suppose I would be showing my age if I said "vacuum advance"

[mmeyer]

Well, it's in the shop now. All of the electrical checked out so Monday they are doing a compression test and seeing where to go from there. Constant missing now, seems to be getting worse.

[mmeyer]

Got my truck back yesterday. Turns out it was sparkplugs. 3 of the new plugs I put in were bad. They must have good at first because it ran good but they got progressively worse. Well, lesson learned.

Thanks for the tips guys.

[Jeremy airjer W]

I'm going to bet it was this

"I have run into more than one of these where the insulator for the center electrode will be bad and the spark will jump before it reaches the gap. You will see a definite black spot on the center insulator if this is the case. "

This happens quite often.

[1johntimm]

This happens quite often.

Does it happen to more of one plug brand than the other?

[Jeremy airjer W]

I couldn't tell you. The only plugs I put in a dodge are champions. I do know that I have not had this issue with the Champion "truck" plug. Its always the standard plug with the really long center electrodes that seem to have the issue.

[Macgyver55]

The only plugs I put in a dodge are champions. I do know that I have not had this issue with the Champion "truck" plug. Its always the standard plug with the really long center electrodes that seem to have the issue.

Same here on both points!

[Scott K]

But dont put the Champion plugs into other models other then Mopar, they just dont seem to work.

[jmd1]

i put bosch fancy plugs in my hemi one time, only to find out they fouled faster than the cheap champion oem plugs it came with. i guess i learned my lesson and after reading the manual it even said not to do it. I always put a bit of antiseize on the threads even the nickel one to ensure no seize up when going it or coming out. same with the grease in the boots. oh well live and learn.

[Macgyver55]

But dont put the Champion plugs into other models other then Mopar, they just dont seem to work.

True that too!