Error Code P0304

[woodhaven22]

Good-day,

I had posted a problem with my 2001 Astro AWD 4.3L van generating a error code P0304.

I used Seafoam and GM Fuel Treatment Plus.

I has been good all weekend and today it rained outside which now has caused this to happen again. Is their a sensor which is causing this problem? why would this only happen when it rains outside.


Thanks

[davesyo]

Code po304 is cylinder misfire .Could be bad wires, cap , rotor , plug or coil.

[ihatemybike]

How old is the cap and rotor?

[Mr_Bowtie]

If it happens when its wet once it goes away you can take a spray bottle with water and spray it until you find the exposed wire or cracked coil or whatever is causing the miss when wet. (motor running/doghouse off)
Or to just band-aid the problem until it gets wet again you can spray the wires and coil and distributor down with WD-40.(4X4 guys don't leave home without it!)

[woodhaven22]

I had everything replaced three years ago.

Does it seem like this could be the problem?

When this does come on, it really kills my gas mileage.


Thanks

[spongebob218]

P0304 is a cyl. #4 misfire. Could be a plug, wire, or cap. Being that it only happens when its wet, I'm guessing the plug wire for cyl. #4 or the cap is bad. Check those parts first.

Could also be an injector or a mechanical issue(burnt valve, etc), but highly unlikely given the symptoms.

[Leeann_93]

If they're 3 years old, you need to inspect them. They tend to have problems with moisture getting under the cap when older and causing a no-start condition.

[adibv5]

maybe your tank water gets in .... did you use that seafoam into the intake? i read around that might clean the engin good maybe helps.

[woodhaven22]

Yes,

I used Seafoam in the PCV hose and pured a bottle of GM Fuel Treatment Plus.