Dodge Repair Questions? Ask a Mechanic for Answers ASAP
Since you just did a tune yesterday, this might be an easy question for you... Is this a 3.9 engine and is there a great deal of distributor shaft looseness?
Not your normal wobble-type, but loose in a manner that you can turn the rotor quite a long way forward and back against the drive gears down in the block. If the rotor tip moves more than 5/16" backward/ forward, I may have the answer for you.
Thanks... I had a feeling it might be a bit sloppy.
What you're seeing is something that tended to happen fairly often on the '92 Dakotas with the 3.9 engine, GRAMMY. The distributor drive gear and block bushing at the rear of the camshaft are worn out. The extra freeplay that you feel when you turn the distributor rotor tip forward and back translates to the wear that's accumulated down below.
The distributor drive gear does double-duty, also turning the oil pump. I can't see a connection between the loose drive and your valve clatter because if the drive slipped, the distributor would go out-of-time and your engine wouldn't run at all. It's another issue altogether.
The camshaft never wears out, only the drive gear. The extra slop causes some banging against the upper block bushing that supports the drive gear and that adds to the problem.
TSB 18-08-93 describes what's happening with your 3.9 and the repair procedure, which requires the use of special tools built just for this problem. You won't likely be able to extract the block bushing without intake manifold removal yourself without the extractor tool, so my advice is to see your friendly local Dodge dealer on this one.
In the meantime, I can offer you some advice that will make it a bit easier to live with the truck while you're waiting to get it in to the shop.
Since the majority of the trouble you're seeing is caused by the distributor becoming retarded, throwing the cam sensor sync out of time and allowing the rotor tip to be trailing (allowing cross-fire), you can rotate the distributor slightly to the left (counter-clockwise direction) and your problem will be temporarily relieved.
It's not handy to get to the distributor hold-down bolt (13mm hex head) but you can tap the housing to the left by using a long screwdriver or drift, tapped by a hammer on the driver's side of the housing. At the base of the upper distributor housing area, you'll see an aluminum protrusion that you can rest the drift against for tapping.
Imagining this is a clock, all you want to do is tap it about two minutes to the left. If it doesn't move with moderate force, you'll have to loosen it a bit first. Don't get medievel on it lol!
Last... if the last 5 digits of your user name is XXXXX XXXXX code, you can't be far from my hometown, 61364.
Write back if you have any questions.
LOL! We're still neighbors... I'm in the class of '58.
Thanks. You can write back using this thread if it concerns this question, otherwise you're asked to start a new question. Just type "dodgerench" onto the question and I'll find it. My specialties are somewhat limited in that I prefer to stick to driveability (running), electrical or emission type issues, but I'm always glad to get mail. ;o)