Pontiac Repair: 1997 Montana chugging bad..., head gaskets, head gasket

Question
QUESTION: I have a 1997 Montana with the 3400 V6 that just this evening started chugging really bad. The Check Engine light is blinking as well. We bought the van with a bad motor (head gasket) so we bought another motor and before it was even installed we had new head gaskets and intake gaskets installed. We are not using DexCool as we were told it was the main reason for gaskets failing. There is no smoke coming from the exhaust and I have not been able to check if there is water in the oil. Please tell me I have abad coil pack or something as I am afraid it's the head gasket again and we've only put less than 10,000 miles on the refreshed motor. Any insight you can give would be very helpful. Thank you.

ANSWER: Hi Mark:

well if the service engine lamp is flashing it's misfiring bad enough that if you keep driving it it will damage the catalitic converter. The most common issue with these is bad plug wires at the coils the contact on the coils actaully rust up and casue the wires to arc thus the misfire. VERY common. if you spray a fine mist of water around the wires you may even see the wires arching.. The other issue could be an injector being plugged That happens on these older engines as well. Just 2 things to look into. But my guess it it's a plug wire issue or possably a bad coil.. Good luck :)


---------- FOLLOW-UP ----------

QUESTION: Thank you for your response to my initial question. I have checked the coils and they seem to be working properly. I checked the three plugs on the front of the engine (#s 2-4-6) and the #6 plug was completely soaked although after I removed the plug and checked it there was a good spark. I've been told the injector is stuck open. It was terribly cold here the other night when I was trying to check out various things and I decided to let the vehicle run for about 10 minutes (I had been told if I ran injector cleaner through the engine that the injector would "unstick") and I noticed that the temp gauge would not go to it's normal operating range. I'm going to try moving the #6 injector to the #4 spot to see if it soaks the #4 plug. Other than that do you have any thoughts? I've also been told it may be the O2 sensor, I'm sure not interested in simply "trying" things in an effort to remedy the problem. Thank you so much for your help!

Answer
The O2 sensor is not going to cause a misfire. It can be a result of an injetor that's stuck open damaging the injetor. Use good injector cleaner! and get a product called to add to the tank from chevron. It's calle thecron. It's an awesome product!