I've got a '99 Jetta 3 with the 8 valve 2L ABA engine. Car is completely stock, and has run fine more or less its whole life.
Abruptly the other day it would lose power and even quit. Initially it seemed to coincide with wet weather. In fact, I thought it was plug wires, and I sprayed WD-40 to displace water from them, and that
*seemed8 to help. But yesterday I replaced the plug wires, and with the car idling I sprayed everything down liberally with a water mister, everything seemed fine - car idles fine with wet (new) wires and distributor/coil etc. I took it for a test drive. Everything was great while it warmed up. Once it reached temperature, it more or less acted like it was out of gas (again). Can't accelerate hard, missing, poor idle.The problem seems to occur only after warm up, but not all the time. Again, intermittent symptoms are if I go past half throttle while driving, it severely loses power. If I back off the throttle, it recovers. If I push it further, it loses all power and will die. Then it's very difficult to restart, and will have a pretty rough idle. (sometimes as it's dying, it backfires and spins the motor backwards!)
Today I can not reproduce the problem. The roads are more or less dry, so again it *could* be water related.
Help! I don't have a fuel pressure gauge. I do feel like it's starved for gas, but again it's intermittent, and I'm not sure how to tell.
-Arthur
Other notes: Last time it was behaving badly, I disconnected the MAF to see if that helped. That did change the running behavior a little, but the problem was still very evident.
It is throwing CEL codes: P0300: random multiple misfires. Nothing else.
Although today I've been unable to reproduce the problem, I did try adaptation of the TB. It failed. I had to manually actuate the TB and tap on it a bunch, and then it passed. I think that's not great, but maybe not the smoking gun.