'02 Montana "gagging"

My Montana is driving me nuts!!! Along with the service dept at the dealership. My van is "gagging" around 60 mph (or above) for no apparent reason. I can't seem to predict when it is going to act up. It's not when it is low on fuel, not when it is hot or cold, although it seems to do it more often if I have had the ac on a lot that day. The RPM's go nuts when it starts missing. It feels like it's jerking, missing, gagging itself. It will stop if you stop driving for about 30 minutes. I can't seem to get it to do it when it's at the dealership so they aren't doing anything to help me. It's so bad that if someone was close behind me at 65 mph on the interstate and it missed I'd be hit (and possibly hurt). This is a MAJOR problem for me, I have 2 kids and it's a high concern for thier saftey if I can't get this fixed soon. The dealership just keeps telling me it isn't saving any codes - arrghh!
I even asked the dealership if the code saving thing could be torn up! They are being most unhelpful!
Does anyone have any idea what this could be? Or how to get my point across to the dealership that is has to be fixed NOW? I've the good extended warranty so I don't understand why they are dragging thier feet on fixing my van.

...Does anyone have any idea what this could be? Or how to get my point across to the dealership that is has to be fixed NOW? ....

Your first call should probably be to the service manager to express your concern in a measured but firm way. See if he is open to the following:

The possibility that the van could be given to the dealer's most experienced mechanic (tech??) to drive to and from work for a few days to see if he can experience the problem. We're talking about trust here of course, trust that the dealership truly has your best interest in mind and will, if it is witnessed observe and then try to figure out what is happening.

Since you need wheels, see if the SM will loan you a car so that you can get around. This one point will tell you how much you are valued as a customer.

If talking directly to the SM doesn't work, you have two options. Switch dealers and find a good one somewhere else. Second call GM customer service and explain what the problem situation is creating for you (as business-like as possible), that you have extended warranty and ask them what they will do for you.

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My Montana did the same when I put in cheap gas. Please keep us posted on the outcome of your ordeal. Hang in there!

Sounds like ignition coil(s). Get them to check them, could be that one is bad and/or grounding out. This sometimes will not be caught by the engine managment computer, and give you no codes.

Sounds like mabie a short some place if it's making your tack jump around
check for a wire in the engine bay that could be grounding itself.

I agree with blazes9395. But more importantly check the coil towers for rust. Pull the plug wires off the coils look for rust on either the metal coil terminal and/or inside the plug boot. This would cause a miss when damp, such as rain, car wash or humidity.

Here is a brief update to my situation. I took my van to the dealership at 5 pm on Tueday. I explained that it had to be fixed and I was willing to let them drive it until Friday before calling GM customer service. I politely then went away, leaving them to "deal with it" (and an empty tank of gas too). I called around 4 on Friday, they have found 2 things wrong and fixed them and still no codes or misses on them. They finally got with it and actually bothered to look at the van, our battery cables were very loose and they found a loose connection/cable (I can't remember which he said but I am sure some of you will know) between the fuel pump and the PCM sensor. The dealership guy that I acutally like dealing with wanted to keep it over the weekend and drive it so now I am waiting for Monday morning to roll around and hoping they finally have it fixed or at least know what is for sure wrong. I've emailed every single post here with all your alls suggestions to him. I'll keep you posted, and thanks for helping me out.

Any update on this? My van is doing the same thing. Another thing I've noticed is that when I am in park and rev the engine to 3100 rpm's it will consistanly drop about 200 rpms and than jump back up.... back and forth....

reving up the van to that rpm kicks in the rev limiter that is designed in to the software in the pcm that is a normal condition.

From my last update - I picked up my van on the following Tuesday afternoon and it has been fine, no problems since. If all the troubles I had was only a loose connection then the service dept was very sorry! I do think that if my van isn't fixed the problem won't resurface until the weather heats back up in the spring/summer here. While they had my van the last time the horrid hot hot humidity broke here leading into reasonable temperatures. I do think it was tending to act up more when the heat was HOT! I'm not totally convinced it is fixed, I'm just waiting to see....