Hi all. A while back I asked about a vibration in my DRV 3500 which only occurred going uphill under acceleration between 40 and 50. It didn't have to be very steep either otherwise ride was smooth at all speeds. The suggestion back then was to check my unjoints and turns out they are fine.

Today I was driving an atypical hilly road for Fl. and noticed 2 things- the rough running always seemed to occur at an up shift (I'm accelerating) and if I got down on the pedal (instead of feathering it trying to get better gas mileage like I usually do) the tranny would kick down and then get no vibration at all thru the gears.

When I bought the van it would kick down too easily on slight acceleration on flat roads and so adjusted the throttle cable which was misaligned quite a bit from the shop manual position. On flat roads every thing was fine after that. Moving to N. Fl. there are hills and my problems became evident.

Does it make any sense that if I overcompensated a little with the throttle cable adjustment to prevent kick down or if the position has changed a little over time that now accelerating up hill especially trying to "feather" the gas pedal that the tranny is shifting into a higher gear a bit too soon for the speed I'm going with the engine under heavy load causing the engine to shudder a little. Like if you upshift too soon going uphill with a manual tranny. I'm thinking I might just have to readjust the throttle linkage.
Before I do that any advise would be greatly appreciated.

 

I would more suspect that what you are feeling is an misfire. When is the last time the van had a tuneup? How many miles are on it? How old are the oxygen sensors? Getting any codes?

 

Bought the 2001 van 2 yrs ago with verified 68K miles. It was a fleet medical transport van and just prior to sale had a problem the sellers mechanic fixed that had caused it to sit for years. I put time and not a whole lot of money in it at the start and it otherwise is a sound vehicle today with 79K miles.
Never did anything electrical so don't know when the last tune up was or anything about age of O2 sensors. The only code I get is PO442 for small evaporative emmisions leak and have had that code since day 1.

 

Think I would start with the tune-up then, and replace at least the front O2 sensor. (NTK or Denso please, skip Bosch.)

 

Makes sense and I'll do it. I'm old school and never tuned up a van with fuel injectors. I appreciate your thoughts very much. Can you suggest what a basic tune up might consist of given only the one error code? I don't really want to do too much or to little. I don't mean how to but just what items please.
Thanks

 

Plugs, definitely. Just use some good copper plugs, skip the rare earth fellers, these engines don't always care for them. I went with NGK's. Plug wires, if they are old and stiff.... (or original.....) distributor cap, and rotor, and a genuine mopar pcv valve. (aftermarket fellers aren't always the correct flow rate.) And don't forget the O2 sensor. (those can be a real drag to get out...... I used a pipe wrench, and a big hammer. )

 

Thanks. Your help is truly appreciated. In a few days I'm headed from Fl. to Ca. and if nothing else am sure I'll save on gas.

 

I followed your advice fortunately- PCV, plugs, rotor & dist. cap in horrible shape. Only thing I haven't replaced is wires- which I suspect are original- because Duralast set supposed to fit my van doesn't w/3 wires too short. Strangely while van runs so much better power wise with much better gas mileage my shimmey is noticeably worse. I noticed when replacing the cap one wire came off with tons of that white powder at contact. For now I cleaned it up and added silicone grease. I'm hoping that might be my problem and increased because the engine is otherwise running better.
Do you know a brand of wires that actually fit (5.9L)? If nothing else should Mopar?
Thanks

 

You can likely get better quality wires from the aftermarket, than the dealer. MSD, Accell, et. al. all make wires. Get a GOOD quality 8mm (at least) wire set. Swap 'em out, and see if it helps. I wouldn't be at all surprised if it did.

 

You were spot on. Took me a while but after new plugs, dist. cap, rotor, front O2 sensor, PCV valve and finally ig. wires (had to order wires to get right lengths- Taylor 8.2 mm) van is running so much better. But the shimmey that was so obvious before is still ever so slightly present at same speed/conditions as before. It is barely noticeable and I could easily live with it but for gas mileage purposes would like to fix it. It's obvious now my main problem was ignition. Do you think I should try replacing the coil? It is prob. orig @ 80K miles now and is the only part of the ig. system not replaced. Thank you so much for your help- I was initially sure it had to be the drive train or tires and would have headed off in all the wrong directions without your help.