Hesitation durring rain, 93 VG30, auto

[NewPaths]

Hi Folks,

 

I'm hoping maybe someone has come across this before, before I throw any parts at this beast. On two occasions, when I left from work, the pathfinder hesitated really bad (felt like a constant mis-fire: the engine/exhaust literally sounded like it was under water!) after it had rained that day. Huge drop in power: struggled to get up to speed. It may be actually rain related, or humidity, I'm not sure. The important point is that it happened *immediately* after I began pulling out of the parking spot, so it's not water getting splashed onto the O2 or similar underneith. (unless it's draining down onto something while sitting).

 

I have some really bad exhaust leaks: at least one on the driver-side manifold (at head or collector, not sure) and on the muffler. MPG was calculated last week at 17.7mpg, mostly highway.

 

After (slowly!) getting on the highway it seemed OK. Actually after warmed up it seemed to run better than usual.

 

When I first bought the truck I ran a 1/2 can of seafoam through the brake booster vac line (how I find exhaust leaks!).

 

After the first incident: I pulled codes, nothing. I pulled cap and inspected cap/rotor: they're worn, but no abnormal arcing on the cap. The two plugs I pulled were marsh-mallowy brown (OK). MAF was cleaned with a good non-oiling electrical cleaner after the first incident.

 

Any thoughts? I dont have any experiance diagnosing auto tranny's, but I can tell mine is shifting a little harsh (fluid is still nice and red, not burnt, and an OEM radiator was installed not long ago by prior owner). Can an auto tranny stumble like this?

 

Thanks,

Jamie

Edited October 20, 2007 by NewPaths

[NewPaths]

Oh BTW, 122,xxx on the dial.

[Paffphinder1989]

Does this only happen when it has just rained outside or it is moist, because mine has had similar problems.

Don't exactly know what it is though...

[yozsi]

old spark plug wires will start arcing to ground on humid days, i bet you just have old worn out plug wires.

[Simon]

Agreed. That's not uncommon on any vehicle. I had that happen with a month old set of wires. Just had a bad one in the bunch.

[93blkpathr]

NewPaths

 

Not sure if you figured it out yet, but my old 93 had the same problem in the rain and I found the ground wire connector on the distributor cap was loose. I replaced it with a tighter fitting connector and the problem went away.