WOT: VW Jetta problem Options

[ruddyboys]

I have a 2003 Jetta 2.0l. Started the car the otherday and the car idled very rough, I noticed the check engine light was blinking and kept blinking for about 3 minutes and stayed on (oh by the way the check engine light has been on for about a month need to replace the O2 sensor) As I started to drive the car it was bucking and had no power, hills I drove up in 5th gear I had to down shift to 4th. Also I noticed I am getting interference on the radio, It radio noise doesn't speed up as the car goes faster just a constant sort of thumping static.

[CoolAirVw]

Lots of good information has been posted allready. But I have a few points I would like to add.

#1 a flashing check engine light means that there is an engine miss that could be "catalyst damaging" this is the only reason the check engine light will flash. Dont drive it unless you want to ruin your cat.

#2 Common misdiagnosis. Some codes (ie 171 & 174) are defined as Lean O2. This means that the 02 is reading lean and could be a bad O2 but is more likely to be a missing engine. During a miss the oxygen in the cylinder is unburned so the O2 sees it and triggers that code. The computer assumes the mixture is lean with the logic that if it see's oxygen that there must not have been enough fuel to burn all the oxygen. But someone will say... if its missing it should trigger a misfire code. NOT ALWAYS! My point is you may not have needed a O2 sensor at all.

#3 The problem with driving around with the check engine light on is that when a "real" problem develops you dont immedialy run out and get the codes. You probably do have misfire codes like 300 random misfire or 301 cyl #1 misfire ect. When your check engine light came on you ran and got the codes checked even though it was running fine. But when the engine starts acting up ect you didn't run out and get the codes checked because the light was allready on.

Point of #3 is get that light out. A engine with a proper working O2 will run better and use less gas and the gas savings would have probably paid for the sensor by now.

example of why #3 is important. My wifes caravan had an EGR code turning the light on. She (Me) ignored it cuz thats just for emmissions. Then when it triggered a Cooling Fan relay trouble code there was nothing to tell us the code was in there because the light was allready on so we didn't know it. All that we knew is that the AC quit working. A normal function of the computer on her car is when there is a Cooling Fan relay trouble code the computer disables the AC to prevent overheating. Well a week later (she mostly drives hiway) her van overheated in bumper to bumper traffic and it was a big hassle. After finding the fan not working and diagnosing it based on the trouble code I found in the computer I realized she had been suffering through with no AC for a week for no reason. We could have known about the problem a week before, fixed it and avoided the breakdown and the tow. (no to mention the risk of overheating and damaging the engine). What if we would have had some shop try to fix the AC? How many misdiagnosis's and parts changes would we have had to endure before they realized it was the fan relay?

Point being. Get those lights off folks.