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.

 

Wow! You sure spent a lot of money throwing parts at it hoping that would fix the issue.

A few questions -

1) Have you removed and inspected the spark plug wires for damaged insulation or broken connectors?
2) Have you removed and inspected the distributor cap for damage?
3) Have you removed and inspected the CKP (Camshaft position sensor) for damage? The CKP is located inside the distributor and if it is damaged that will wreak havoc on the ability to correctly fire.
4) Have you inspected the CKP connector for damage? Also be certain to inspect the harness for the CKP for damaged insulation.

Other items for consideration:
- The condition of the connectors and wire harness of the injectors in question.
- Actually removing and inspecting the inlet side of the injectors for debris. This will require removal of the fuel rail and replacement of the upper and lower injector o-rings upon reassembly. Never re-use injector o-rings.
- Removal of the fuel rail and inspection for debris. Cleaning the fuel rail is a good idea at this point. See the previous note about replacement of the o-rings in this situation as well.

 

How's oil consumption? Have you checked the plenum?

 

+1 for checking the things VW and HeyYou posted.

Also, Thank YOU for posting the description of the codes you are getting.....I usually skip over threads that post the code number as I am too old and lazy to go look them up.

 

P300 is a Random Multiple Misfire
Then, 301-308 means a misfire on the cylinder that corresponds with the last digit in the code. I know this as I've been down this road before.

 

Exactly. As I recognize a number of tranny related codes, these are not familiar to me, but OP included text describing them, so I knew what the problem is, and how your and HeyYou's response was approriate to problem.

Some of us are all too familiar with some codes, but not necessarily others. I detest having to do a search to find out sometimes. So I apperciate the details as most noobs fail to do this.

 

I agree.

 

Last weekend I re-checked all spark plugs no damage only white/grayish discolored electrode tips on all the bank one side. Also saw brown spots on the white ceramic part. Theses spark plug's are barely 3 months old and they are champion copper. I also checked the plugs and ohmed them out. These plugs are also 3 months old.

I have not recheck the cap and button recently. They are about 7 months old and I have not replaced or checked the CKP sensor or its related connectors. But I have several times shook the cables while the truck was running but did not notice any issues. But I am in the process of checking for frayed or damaged wires.

I am thinking of checking the timing and the compression. But its hard to say if its the timing/compression since this issues comes and go.

 

Timing is not adjustable. It is dependent on correct signals from crank sensor.

Since all your misfire codes are on one bank..... one of the commonalities there is the fuel rail. (and I would point out that it is the side that gets fuel first too....) You mentioned that the plugs look like they are burning lean... I would be real tempted to pull the fuel rail, remove the injectors, and see if they are loaded with crap.... while it's a part, clean it out.

 

I had realized that the fuel comes in first through that side. So are you saying while fuel on its way up that side got clogged first. Just trying to understand something.