Went to the beach this weekend and the D was humming. 18.2 mpg (highway of coarse), not a problem.Now as for the ride back, at idle she runs real rough. Stopped in at Auto Zone to run the computer test and 8 cylinder misfire. Checked the wire from distributor to plug looks good. Just for giggles replaced #8 wire ran fine for a while. Here is the interesting part at idle sucks, accelerating smooth until 50-55mph, thing misses likes the dickens. Once above it smooths right out with intermident misses. From dead stop if I accelerate with a strong purpose, 2 mpg, not a problem right through the trouble zone. While I think about it it misses when I make a slight change in accceration, so I thought an injector .Filled the tank up and addedLucas injector cleaner and ran it 180 mile back from the beach, no change, pull in the driveway "Check Engine"coms on and it then starts to runs smooth. ??????????????

Any thoughts, OBTW 99 Durango 5.2 & 4X4.

 

Go to auto zone and they will pull the code for you. Get back to us with it and we can be of more help. See if autozone has a pressure tester that you can "rent" to test the compression on #8 and the others while your at it...

 

I was going to rum back up this afternoon after work and get the code but why check compression? At more points it runs fine other than around 50-55 it runs smooth.

Will post back this evening

 

It's just a good idea to check and know your compression. This can also show you many things about your motor. Get the code read first tho.

 

[sm=americanasmiley.gif]Real quick update, under the weather so ain-law came over and pulled #8 plug. white, dry and gap was at .069. The electrode tip was thinner than the rest, he ran to AZ and they were out of Champion ( I read, NO PLATNIUMS) he gat a autolite instead gapped at .040. Started up and runs great he siad no flux in the low rpms or miss. If feel better tomorrow going to take to AZ for a code and then to a buddies place he has a compression gauge just in case. Do think this coun be as simple as a bad plug? regardless if this holds till the weekend i'm replaceing plugs and wires. What is recommended for plugs and wires, 30,000 or 50,000. I know I'll use champion plugs, but were did Mean Green get his plug wires from? Or a good set and mm you all recoomend

 

I haven't done my wires yet. The idiot that owned it before me put in no name plat's and the funny thing is that I got it with a little under 30k miles.
As for your question get Champions and stick with them. If you have the money I would invest in MSD wires, cap, and rotor. The get 8.5 mm wires.

 

I'm still going to AZ tonight and get the code read. I guess I should have checked the plug in the beginning. I'm going to try to take a pic of the plug and post. but what I know about engines if this one plug is starting to go the rest should surely follow. Could this have been the underlining problem?

Thanks again and Mean i'm going to get MSD wires, MSD Cap and MSD rotors. What about ACCEL brand?
Thanks again guys!!!

 

I have a 1998 5.9L. And here is the part numbers I used.

https://dodgeforum.com/m_457513/tm.htm

 

Basically as long as it's not cheap crap go for it. Oh and you should be changing at least the wires and plugs every 60k miles but I would change it all.

 

Went to AZ and had them run the run what codes were on her and they are as follows p0753 Transmission solenoid, P0307 misfire#7 & p0308 misfire #8. Ordered my parts for a tune up this weekend. Th eold plugs are Champion but the person that put them in must have gapped them off frm the .04 they should have been. Will post back after I tune her up.