Transmission and Idle woes

[crag277]

I've thuroughly searched these forums for a similar problem, but nothing quite matches all the symptoms I'm having. Here goes.

My car:
92 Lumina Euro 3.1 w/ 96,000 miles
Exactly one year ago a tune up was done and the plugs and plug wires were replaced.

Problem:
1) The first issue isn't a big deal, but its kind of annoying. In high humidity and rainy conditions the car has a very rough idle and significantly more hesitations and sputtering when trying to accelerate. Dry weather it runs great.

2) After the engine is up to running temperature, and ONLY after this happens, the car bucks and shutters in 3rd and 4th gear only after the torque converter actually locks in gear. It feels like a car with a manual trnasmission stuck in too low a gear, however the shift points have not changed. When this happens I have no choice but to back off and do all I can to hold the car at its current speed. There's no hope of further acceleration unless I force it to downshift. I have routinely checked the fluid, noticed a small leak and have kept it full, but this does not elliminate the problem. One thing I have noticed is the days the transmission is acting up the worst are also bad days for the idle issue. I don't see how the problems can be related, but this is just an observations I had.

Any ideas? Thanks!

-Eric

[richtazz]

On a dry evening, spray the wires with water. Start the car and see if you can see spark arcing between the wires. It's not impossible to get bad wires out of the box, especially if you bought cheap wires or ones made by Bosch (they are notoriously crap). IF spraying the wires doesn't make it run crappy, or you don't see them arcing, you could have a bad plug(s) as well. Again, if you bought Bosch plugs, there could be your problem. If you have an old timing light, you can use it to check each individual plug's spark pattern. Any with gaps in the flash pattern would indicate a bad wire or plug on that cylinder. If you have two that are acting up that are on the same coil, that would indicate a possible bad coil.

[Jonn]

Originally Posted by richtazz

On a dry evening, spray the wires with water. Start the car and see if you can see spark arcing between the wires. It's not impossible to get bad wires out of the box, especially if you bought cheap wires or ones made by Bosch (they are notoriously crap). IF spraying the wires doesn't make it run crappy, or you don't see them arcing, you could have a bad plug(s) as well. Again, if you bought Bosch plugs, there could be your problem. If you have an old timing light, you can use it to check each individual plug's spark pattern. Any with gaps in the flash pattern would indicate a bad wire or plug on that cylinder. If you have two that are acting up that are on the same coil, that would indicate a possible bad coil.

If i may add, i had a coil go bad and bought a new one at Advance Auto, it lasted about a couple months till it failed. Said the Hel with Advance, got a original from a yard and its been fine.

[crag277]

Interesting... Next dry day we have up here in the northeast I'll have to give this a shot. Today it's pouring rain, and the car didn't do so well on the way to work this morning.

Any ideas on the transmission? Maybe just a flush of the old fluid and a new filter? (hopefully)

[Mediaman67]

I had this exact problem!

You'd swear it's the tranny... but it's a bad wir, etc...

In my case, what happend was, anytime there was any moisture in the air, the wire would short, and this is most noticeble in OD, esp when climbing a hill... car would buck, etc... low RPM and under a load... just like you are discribing...

you may have a bad ign mod too... but my point is, I'd bet it's ignition related, and not the tranny... I could be wrong...

I would just do a full routine tune up, and see if that helps.

If the tranny shifts fine when it's dry, it should be fine when it's wet too... usually, tranny problems are constant... which is sort of a good thing I guess... :-)

BTW - Does anyone know how you can change the shift points if I wanted to?