98 jetta 2.0 186k miles. The engine dies after sitting at a stoplight or at idle after about 15-20 sec. CEL is on intermittently (blinks for a while, steady, then off, then back to blinking, and steady etc.) Code read missfire in #4.I have replaced the following: coil, wires, dist. cap, plugs, throttle body (used), MAS (used), fuel filter, checked all vac lines, air filter ok. I have ablsolutly no idea where to go next, maybe the scrap yard. I have obviously dumped a lot of cash into this car, and am fed up. Can anyone give me an idea where to look next??? I'm desperate!
thanks,

 

Have no idea what the problem is. However i've had
some brain teasers like this. Just repaired a Jeep cherokee
doing the same thing, it turned out to be a radio station
they were driving by and the signal was upsetting the
computer. Do you know of any radio stations, ham radios,
or other things that might send out a signal in your area of
driving? Volkswagen was very bad about this when they
first came out with the computer thing. There isn't a real
fix on this except stay away from the signal. However we
did a new sparkplug replace and a high amp battery replace
so the computer would be sure to have enough reserve
current, and that seemed to cure the Jeep.
One other thing be sure your using the correct spark plug
and not any of these super plugs they cause the same
problem if the car doesn't call for them.