Van is giving an occasional misfire on cylinder 4. It seems to run fine for a while, then starts acting up, only to be fine again a little later.
I have tried swapping the coil pack from 4 to 5, with no change (still only shows up on 4), then swapped the plugs between 4 and 5 with no change, then moved the coil and the plug from 4 to 5, with no change. I have pulled three of the plugs, (cylinders 3, 4, and 5) and they all look the same - pretty close to new in appearance (they only have 25-30k miles on them) - no fouling, no cracks/chips in the insulator, etc. I did find one plug that seemed a little loose (cylinder 3) which was weird, but the plug itself looked fine. Also played around with disconnecting different coil packs, and they all result in a drop in engine speed, so they all seem to be working.
At this point, I guess I need to check the injectors - my thought is that if I am going to go through the trouble of pulling the fuel rail and shuffling injectors, I might as well just buy a replacement injector and swap out the one in cylinder 4. One question I have for those that have done so - how is the quality of aftermarket injectors? rockauto has a number of options at about half the cost of an OEM injector.
I just put a thing of techron in the fuel tank (it has half a tank) so I will run that through and see if that helps, as well. If not, I'll probably go with the injector as that's about all that's left.
I have tried swapping the coil pack from 4 to 5, with no change (still only shows up on 4), then swapped the plugs between 4 and 5 with no change, then moved the coil and the plug from 4 to 5, with no change. I have pulled three of the plugs, (cylinders 3, 4, and 5) and they all look the same - pretty close to new in appearance (they only have 25-30k miles on them) - no fouling, no cracks/chips in the insulator, etc. I did find one plug that seemed a little loose (cylinder 3) which was weird, but the plug itself looked fine. Also played around with disconnecting different coil packs, and they all result in a drop in engine speed, so they all seem to be working.
At this point, I guess I need to check the injectors - my thought is that if I am going to go through the trouble of pulling the fuel rail and shuffling injectors, I might as well just buy a replacement injector and swap out the one in cylinder 4. One question I have for those that have done so - how is the quality of aftermarket injectors? rockauto has a number of options at about half the cost of an OEM injector.
I just put a thing of techron in the fuel tank (it has half a tank) so I will run that through and see if that helps, as well. If not, I'll probably go with the injector as that's about all that's left.
