2002 Jetta Engine light came back on

engines
lights
jetta
volkswagen
misfire

#1

Check engine light came on last week, got the code read, "misfire cylinders 1&2. I changed the plugs and all the ignition coils. I disconnected the battery to reset the check engine light to see if it would go on again and it did the next day. So now what and how much is this gonna cost me on top of $4 a gallon for gas! lol.


#2

Same code? same cylinders?


#3

Many older cars you could disconnect the battery to reset the engine computer to base settings; not newer cars. You need a scanner to erase the code; otherwise, it may take many “trips” to reset the computer after the problem has been fixed. You may have fixed the misfire on your engine.
You like to change parts to “fix” problems; swap #1 & #2 fuel injectors with #3 & #4. If the misfire codes move to #3 & #4, you’ll know the fuel injectors caused it.


#4

I agree . .

Also, you might want to have the computer scanned by the dealer or an independent VW mechanic. The are many codes the engine can throw that will not be read by a generic OBDII scanner. These codes are only pulled with the dealer’s scan tool or a specialized tool like a vag-com.


#5

I kept getting a check engine light on my '98 Blazer at about 140,000 miles. The code was manifold absolute pressure. Replacing the sensor did nothingexcept waste several hundred dollars. The dealer finally suggested a possible intake leak. I knew it was just a guess. I ran it by a very experienced private mechanic who said that the fuel injectors were just old. He advised to start with a fuel cleaner (he recommended Lucas) and then add a few ounces of ATF to the tank every time I gassed up. End of check engine light and start of better performance.