We have recently upgraded our Astro from our 1999 AWD to a 2004 AWD. I am super happy with it except I am getting a misfire (check engine light flashes) when the van is under load for a duration. We of course use the van to tow our boat, and it does great but when climbing a long hill the check engine light will flash. As soon as we crest the hill, the light stops flashing, and most times it does not even set the a code to keep the light on. The light goes off and we continue driving as normal. The van is now doing this even when not towing. There is a long hill near our house, and when trying to maintain 50-55 up the hill, the light will start flashing about 3/4 of the way up. The biggest problem with this is when the misfire happens and the timing retards the van looses power on the hill. This is a major problem especially when we are towing the boat.
The couple times that it stored a code it was a random misfire, or a misfire cylinder #2. I have tried all the normal fixes, plugs, wires, cap, rotor (all AC Delco parts), and now even a distributor. Fuel pressure measures right and I replaced the fuel filter. A trusted friend of mine who is a mechanic said that he has seen this problem in other astro vans and the cause was a worn timing chain. The slight wear in the chain is enough, when under load, to cause enough of a timing mismatch to cause a misfire. Has anyone else heard of this?
He said that as a temporary fix he has ground out the hole in the distributor clamp and advanced the timing slightly. This was enough to compensate for the wear and temporarily fixed the misfire issue. He willingly admitted this is a band aid fix. So I tried this and the first couple times over the mentioned hill, there was no misfire. However it is still happening and I want to get it fixed right. I am willing to do a timing chain if that is indeed the problem.
I just want to note that other than these hill climbs, the van is running great. Even when the misfire happens, there is no noticeable issue until the light flashes.
So before I go any further, I thought I would throw this up here. Anyone have any insight on this? I am open to any input.
The couple times that it stored a code it was a random misfire, or a misfire cylinder #2. I have tried all the normal fixes, plugs, wires, cap, rotor (all AC Delco parts), and now even a distributor. Fuel pressure measures right and I replaced the fuel filter. A trusted friend of mine who is a mechanic said that he has seen this problem in other astro vans and the cause was a worn timing chain. The slight wear in the chain is enough, when under load, to cause enough of a timing mismatch to cause a misfire. Has anyone else heard of this?
He said that as a temporary fix he has ground out the hole in the distributor clamp and advanced the timing slightly. This was enough to compensate for the wear and temporarily fixed the misfire issue. He willingly admitted this is a band aid fix. So I tried this and the first couple times over the mentioned hill, there was no misfire. However it is still happening and I want to get it fixed right. I am willing to do a timing chain if that is indeed the problem.
I just want to note that other than these hill climbs, the van is running great. Even when the misfire happens, there is no noticeable issue until the light flashes.
So before I go any further, I thought I would throw this up here. Anyone have any insight on this? I am open to any input.