I have 1998 dodge ram v6 keep getting misfire codes, p0300, p0301, p0303 and p0305. The misfire is always on bank one. They may take turns on bank one any where in between p0301 to p0305. I have done the following.

1. Sprayed all gasket areas with carbon spray found no leaky gaskets.
2. Checked vacuum line no leak and has strong vacuum.

Replaced the following.

1.TPS
2.Spark plugs twice with auto lite and champion copper.
3.Spark plug wires three times with autozone duralast wires.
4.IAC valve
5.MAP sensor
6.Purge solenoid -twice
7.Crank position sensor
8. All related fuses to fuel and ignition.
9. adjusted throttle position cable going to transmission
10. Several tank fulls of lucas.
11. very religious with all fluid changes
12. PCV valve.
13. Air filter twice.
14. distributor and button duralast from autozone.
15. replaced alternator due to a dieing alternator.
16. followed tsb 18-48-98 that pertains to plug wire rerouting several times..
17. Replaced both upstream and downstream 02 sensors.
18. I have read several post and videos and they all seem to take me around in circles.
19.Ohmed out the injectors on the lean bank and they are all about 14.6 to 14.8 ohms
20. I have done seafoam through the brake booster and there were no white smoke atleast not a lot.
21. Replaced with a new cat last fall and had it re-check last month.
22. recently remove the muffler it was falling apart.
23. air temperature sensor
24. coolant temperature sesnor

I tested the fuel pressure several times while the truck was running at its worst and at its best and found the pressure to be good at 52psi. But when engine started the pressure/needle on test gauge would vibrate very quickly between 52 and 54 psi while running.

I noticed that the plugs on bank one are always lean which are cylinder, 1,3 and 5. while the plugs on the other bank is fine shows normal color.

The vehicle does not idle extremely smooth you can hear a slight roughness. While driving the transmission will shift down to a real low gear even if going down a hill sometimes or even up. It does this when I am trying to speed up. Its like when the misfiring is occuring the transmsisission labors. Somedays the truck runs great no issues but thats very rare.

I even re-sealed the gasket over the distributor with rtv to keep rain water a way from trickling down there and that does not work.

The longest I have been without any issue is after I replaced the purge solenoid and it went a way for about a month. Then came back. I replaced it again and always getting these codes back.

I am binging to think its a clogged breather on that side or bad valve or head on that side. But what would explain 1 3 and 5 cylinders always misfiring.

Can some one please help I really love the truck it fits me and my needs very well.

 

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