That sucks. It may be prudent to pay for a dealer diagnosis, then fix it yourself. I know it's an outlay, but it save you some $$$ and further headache.

 

You may be right, but I think they guess on what is wrong. When it's cold seems ok then at operating temp you feel a miss. The old heads the exhaust valves had no margin left.

Update; I'll give a little of what I have installed on the dakota. I have dual fuel propane. The system has injector simulator to fool the ecu that the injector is firing. With that said I went the local auto parts store and rented a noid light for the injectors. Comparing to the other injectors, #5 was dim to no light so the simulator has extra wires switched wires and now it lights. It works now, but I think a injector simulator may have be replaced or eliminated if it happens again.

 

Well, they do have more diagnostic tools at their disposal. Even so, their guess will be better than yours because they've likely seen it before.


There is also this... http://flatratetech.com/