P0300 & P0301, P0306

[Kurt Koseck]

Got the check engine light a while back, July. Took the car to a dealership and they said the #6 spark plug wire is bad. Dealership also recommended a fuel rail cleaning. Price seemed pretty high, over $400. So, I did some things myself: changed all sparkplug wires and put new spark plugs in. Also replaced PCV piping and valve cover gaskets. Car ran just fine for last month. Then this morning, car starts and seems to have a misfire, and then the check engine light comes back on. So I VAG it, and get P0300 and P0301. Seems like the same problem as before. I reset the codes, and drove 60 miles with no problem. Now I'm going to put some fuel injector cleaner in the gas and see if that makes the problem go away for good. Another option may be to replace the coil, however this can cost over $200 so I want to make sure before I purchase. I have a 1998 2.8 litre, so there is no ICM to replace.
Any other advice?

Thanks,

[Kurt Koseck]

Started putting fuel injection cleaner in the gas tank. Used about 3 cans over a period of three weeks. Haven't had a problem in over 6 months. Now that I saw that, I'll probably get the code! I think that the dealer had it right when they said that the injectors were fouled.

[auditech79]

Its really common for the 2.8L engines to get carbon build up on the intake valves. From time to time you can do the old school fix by taking off the main intake line, and spray some chemtool carb cleaner in there while someone else floors the motor. This will suck the chemtool to all the valves and break the carbon off and into the cylinders. 1-2 cans is all you will need. I've seen cases where there was so much build up the car wouldn't even start, ran some chemtool in there. Fixes it everytime.