I am hoping that maybe someone out here can help/point me in the right direction. I have a 2001 B3000 V6 standard transmission. It has low miles, less than 10K. I don't drive it often, but when I do it is for long distances (freeway primarily), and some light towing. The problem I have with it is this. Ever since I bought the truck, I can feel that the truck is missing and losses power momentarily on a couple of cylinders as I am going down the road. The truck has a hard time going up hills at freeway speeds. The truck idles really rough, going from about 900rpm, dropping to under 500 RPM then bouces back up, and then back down again. When I have a load in the bed, I can really feel the loss of power.
I have taken it back to the dealer (actually several) and the first time they changed the coil unit. but since then, they "can't find anything wrong". There is no check engine light that comes on, so they say there is nothing wrong. I have gone on test drives with them, they claim they can't feel anythhing.
I have tried to figure what is going on. While at idle I put a timing light on each plug wire to see using the light, if each plug is firing consistently. I found that 2 of the 6 cylinders stop firing for up to 3/4 to 1 full sec whether at idle or reving the engine to about 3000RPM. the other 4 cylinders are strong and consistent firing regardless of the rpms. The ones that drop out consistently drop out, i.e regardless of the rpm range. when they do drop out, the truck's idle slows way down, the engine shudders, etc....it is ugly. But again I never get a check engine light.
So does anyone have any suggestions. I really like this truck except for this problem which drives me nuts! I am trying to figure out how best to fix it, if in fact it can be fixed. I am trying to figure out if this is "normal", if I have an ECU problem, or ????
Any help would be REALLY appreciated!