2.6 misfire

Hello

I recently just picked up a b2600i and I'm looking for some help. The truck is in pretty good shape for an ohio truck and only has 92,000 miles on it. The problem is it has a misfire I can't figure out. It gets worse as the truck warms up.

So far I have replaced
Spark plugs
Wires
Cap and Rotor and distributor.
Ignition coil
ECM
O2 sensor

None of witch seemed to help with the misfire. I took a video to show what its doing.

https://www.youtube.com/watch?v=kULR5Kb8OtM

I'm also looking for the timing procedure as well having replaced the distributor. I picked up a chiltons manual but all it mentions is 5 degrees with test connector grounded. Any help would be greatly appreciated as I'm new to the Mazda scene. Thanks!

It sounds like you might have a vacuum leak maybe between the intake manifold and the head, seeing it gets worse when the engine warms up. Use a can of carb cleaner with a pin point nozzle and spray it around while the engine idles and that might help you isolate where the leak is coming from.

Another thing you might want to do is a compression check. Your video shows a dead miss and a compression check could isolate that issue to a burned valve.

Tried the can of carb cleaner trick but did not find and vacuum leaks. I don't think it could be a valve because at times it will run just fine. Starting to wonder if its a bad injector.

Did you check the ECM circuit board for the typical capacitor leakage? That seems to usually cause the idle to not work and not a miss, but anything is possible. There are write-ups on this forum on what to look for.

I swapped in a remanufactured ecm figuring that may be the issue and it didn't make any difference.

Still looking for info on how to set the timing as well.