In an effort to boost the MPG on my Dakota, decided to put plugs and plug wires on it this morning.

Found this little gem when I pulled the cap off.......





Now, mind you, it started fine and seem to run fine. No obvious miss or real roughness.

Put all my parts on, WOW!!! What a difference! It was almost buttery smooth and I now had a traction problem taking off from a dead stop (roads are damp, wasn't doggin' it).

Got home, turned it off. Cleaned up my work area, went to leave again, and, its running worse than poo......stalling, running REAL rough. Huh? When I parked it, it was fine. Doing nothing but letting it sit and restarting it, it runs terrible. Its bad enough I can't drive it.

I've double checked my work. Double checked the cap, can't find any issues.

I'm at a loss. Ideas?

After typing that post, I went out, re-rechecked my work, still found nothing wrong, fired it up, and it was buttery smooth again.

Drove it 2 miles with no issues, still smooth.

Maybe computer was adjusting to new parts?

I had a similar problem when I changed the battery on my Ram. After a couple of minutes running it smoothed out and ran fine. Did you disconnect the battery?

Just got back from a 30 mile round trip. Truck ran flawlessly.......as long as it was moving. If I stopped briefly for a stop sign, it would dead miss once. If I stopped for a lengthy light, it would dead miss up to 5 times.

By 'dead miss' I mean a miss that you couldn't help but notice, not one of those soft ones where you're not sure if it did it or not.

And of course, its raining steadily now, so, I can't look at it anymore today.

Did you replace the Distributor Cap or just the rotor..????

Rickster

Cap too. There was a pretty good gouge from where the rotor hit....



Marked each wire, and pulled cap off with wires in place. Installed new cap and followed wiring order from old cap.

Checked, rechecked, and checked again that I didn't bust or pull loose a vacuum line that runs across the back of the engine.

I'm lost.

I would replace that cap and rotor with good parts from Napa

Rickster

Go get one of these and drive around with it displayed in the windshield. The truck will know you mean business and straighten up.

No NAPA's close, went with BWD brand. The cheap Chinese caps were smooth inside, no ribs. The BWD cap has ribs inside and looked/felt like the better piece.

I used Autolite plugs and wires. The truck had Champions in it, but, I've ALWAYS had problems with Champions, never had an issue with Autolites. Plug wires, basically the same deal as the cap. Didn't want the cheap chinese junk, but, didn't see the need to fork over $$$ for something like MSD wires, especially for a 150K 3.9 V6.

Make SURE the cap is fully secured with BOTH screws fully engaged. DAMHIK

Robert

Don't know if you disconnected the battery or not but I would still check for a loose ground or clean all the ground cables that connect to the engine and firewall just my

I bet whoever screwed up the cap/rotor job before you twisted the distributor to get it to run, now it needs twisted back to the correct position.

Pull the cap, twist the crank till it is at TDC and check to see if the rotor is pointing at the "1" on the cam plate (if 180 or so out turn the engine one revolution) then if it is off twist the distributor to line up the "1" and the tip of the rotor.

It is more accurate with a scanner but this will get it close enough to run correctly.

Yes, screws for cap are tight, and I made sure no wires were pinched and the mounting service was clean. I carefully blew out all the plastic bits the original cap left behind (didn't use full pressure on the air hose).

When the weather breaks, I'll check timing.

I'm kinda at the mercy of the weather, and of course they say its supposed to rain all week.

Thanks guys.

my 92 dakota does the crappy run after shutdown,been doin it for years,started about the same time as the fuel started getting changed for emissions,its really bad in warm weather
by the way my dist isnt moveable.there is a slot it the shaft that the hold down fits into and holds it in one place,also a bad crank sensor will make it run bad after a warm shutdown,ive heard of people slotting the holes in the crank sensor to advance the timing some,i never tried it

Correct. The drive ability problem is not from the fuel timing being messed up it is from the wrong plug getting fire.

take a good look at a 92 dist,on the housing there is a cut back spot where the hold down fits into,with a different style or modified hold down it can be made to turn,look up a picture on rock auto,you can see the recessed place on the body of the housing

You said it was raining?? Spray the cap and wires with WD-40 and see if makes a difference. Could be a crappy cap even though its new. Or a plug wire not seated right. Just a guess though.

The last set of Autolites I put in a vehicle (a '79 Jeep CJ7) I was not happy with, it had a miss until I reinstalled the old plugs. If they didn't look fouled I'd try putting the old plugs back in it just to eliminate the plugs as a cause.

OK, stupid question time......

If the plenum gasket is 'bad', will it suck less oil with a substantial vacuum leak?

If said vacuum leak is fixed, could I be oil fouling the plugs at idle? (that occasional dead miss I'm getting).

I'll tell what I found after a response or two.

(even at the risk of making my Dakota look like a complete POS, I'm trying to learn here)

Does this truck have an EGR valve on it?

If the plenum gasket is bad, you will suck a lot of oil into the intake and you could have a vacuum leak. If the plenum gasket was replaced and the vacuum leak was fixed, and your still sucking in a lot of oil, the oil is coming from another source, like the bottom of the intake gaskets, by the rings or through the valve guides.

Did you pull the intake? Gene

Truck runs about the same, no worse, maybe a little better actually, but I still get the occasional 'dead miss' sitting at a light.

Been racking my brain try to figure out what I might have done. I was a little distracted and rushing because of approaching rain when I swapped everything out.

Then, I thought of it.

While routing the pass. side plug wires, I noticed the hose for the PCV was barely on (at the manifold), so, I just pushed it on and went about my business.

Looked at the hose tonite. Yeah, its as hard as you'd expect 22 year old hose to be, BUT, the underside is missing a chunk/section as long as the fitting coming out of the manifold. Looking down on the hose, you can't see it. With the hose barely on, this left the manifold port open mostly sucking just air. When I shoved it on, it was far enough that it was drawing from the PCV again.

The missing piece is not laying down in the recesses of the manifold. Deliberate action by someone?

When I posted the video of my truck in another thread, someone mentioned the idle sounded a little high. Hmmmmm.

I haven't been able to swap PCV valves because the grommet is rock hard.

So, with the hose hooked up, could it be sucking oil now?

Forgot to mention, I haven't pulled the intake yet. I have all the parts, just need time and a day or two with no rain.

So the truck only runs like doo doo at idle correct? the EGR valve if sticking open can cause a rough and want to run like crap at idle condition if it is opened at idle. The egr is used at part throttles to purge some exhaust gases into the combustion chamber to reduce the production of NOX for better emmisions. You could have a EGR valve that is sticking open after you drive it and come to a stop or off throttle and allow it to idle.

Next time you start it up and it is running smooth, unhook the vacuum hose to the EGR valve and then road test it and see if it idles better again.

Also fix your PCV hose and grommet, that id for sure a vacuum leak and causing the high idle condition. Might aswell put a new PCV valve in there while you are at it.

I'm thinking its a plug wire. When you moved them around when you replaced the cap, it boogered one of them up on the inside. Now when you hit a bump or move them, it may make contact or not. Again, just a guess.

Try to narrow it down and see which plug isn't firing and see if it is always the same one.