98 Jetta GT - air conditioner / low idle / stalls?
 

So I've had quite a debacle with my 98 Jetta GT over the last few weeks. It's got about 146k miles on it. Has been in great shape (except for a cruise control with a mind of its own) I'll start you all out with the history over the last few months:

Car was running great but would nearly stall during or after rainy days. Replaced the distributor and rotor and everything was fine.

About a month ago, I noticed the car would stutter and/or stall at low RPMs when in gear -- usually 2nd or 3rd gear (sometimes first) when downshifting or coming around a corner and releasing the clutch back into gear (usually 2nd, sometimes 3rd). Check Engine light was on.

THEN, last Saturday the car stuttered/stalled (as it had been lately) but wouldn't restart. The starter didn't turn. Just got a click. Had AAA tow it to a shop. We were able to push-start the car, so we knew it ran. Replaced the starter. They also said they looked into the Check Engine code and it said there was a short in some wiring to the Master Air Sensor or somesuch? The oxygen sensor maybe? They replaced the wiring but said it didn't totally solve the problem.

I got the car back from the shop this morning and started it up. LOW LOW Battery, but it did turn, and the car started. The idle was lower than I remember hearing and feeling. And would pulse between 7rpms and 4/5 rpms. After about a minute it warmed up and stayed steady at 7rpms... which still felt low. I drove it out of the lot and it seemed fine. However, at a stop and at idle, if I engage the Air Conditioner, the idle drops to 4/5 and pulses again. The guys at the shop DID warn me about this. If I drive with the A/C on, it drives fine, until I downshift (or engage the clutch and coast/brake), when the idle drops too low and it stalls. It DOESN'T stall if the A/C is disengaged. The guy at the shop said he didn't want to adjust the idle because it was on spec (but sounds/feels lower than I remember -- and I've been driving this car for YEARS)

Could the car just need a tune-up? New wires, plugs and a timing adjustment? (It's already got a brand-new Cap/Rotor.) Could the battery need replacing? I want to drive it for an hour or two tonight to recharge the battery, maybe the A/C is pulling too much juice and the engine's compensating?

Any advice before I bring it back to a shop? Maybe a VW dealer or specialist directly?

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Oh, and also, the muffler rattles over bumps. I initially thought my rear suspension was going, but the guys at the shop said that there's some bracket that holds the muffler that's come loose and they don't have welding equipment to lock that down, to take it to a muffler shop.

Thanks in advance for your advice!

Bill

RE: 98 Jetta GT - air conditioner / low idle / stalls?
 

did they check the coil? they can give you some strange problems, and really don't like getting wet.