Engine Performance problem
1998 Volkswagen Passat 6 cyl Front Wheel Drive Automatic 84500 miles
For a couple of years I've had an ongoing problem with stalling. Sometimes my car will sputter, hesitate and then stall if I am traveling at a slow speed, but mostly it stalls if I am idling, at a stop, or about to stop. It has never happened in winter, a cold day, on the highway, or at high speeds, and it only seems to happen in warm or hot weather.
In 2005 the vacuum line was replaced.
In April 2007 the Intake Cleaner was replaced. They said there was carbon on the throttle body or carbon in the filter… Anyway, whatever it was, the problem went away temporarily, but returned.
In Sept 2007 the car lost significant power and went into a limp mode several times (the transmission panel lettering on the dash turned black) before I was able to get it into a garage. Most times after I would restart the problem would go away and it would drive normally. The mechanic replaced the Mass Air Flow Sensor, and the problem recurred a couple of times again, then went away for a while, but it has returned again and on one day it must have stalled 20 times. I'm sure this isn't good for my starter…
Some time in 2006 (?) Or earlier the coolant temperature sensor stopped working – also only works intermittently. Mostly reads cold, sometimes goes to middle. I believe there may be a connection with this and the problem.
I’ve also researched and similar problems have cited the following as solutions:
• Y-hose or the PCV hose
• Coolant gauge problem
• Sensor in the main air intake
• Idle air control
• Clogged fuel filter
• Throttle body cleaned
I’ve spent close to $500 on this problem and it’s still not fixed. Fuel pump or line would seem like a likely answer, but the warm weather connection makes me wonder if it’s related to the temperature sensor mis-reading and shutting down…
Would really appreciate anyone who has experienced this, providing me with a solution… Thanks.