P0305B - Cylinder 5 misfire

[mawp]

Hi all, I'm looking for help on a CEL that I got the other day.

I had a buddy with a scanner run it for me this afternoon and it came up as:

P0305B - Cylinder 5 misfire

I replaced the cam sync a few months ago and everything was fine until a few days ago when going up hill it started to misfire badly @ high RPM.

Can someone lead me in the right direction as to what steps I should take? I don't want to bring it to a shop and although I took Auto Shop in high school I'm not used to working on cars much.

Thanks in advance.

2003 Ford Ranger XLT X-Cab, Automatic, 80,000 miles with a 3.0L V6

 

[AKBroncoII]

Change the plugs and wires. I doubt it's ever been done.

 

[mawp]

Probably not. I bought it with 50k on it so I have no idea if it's been done or not.

 

[mawp]

Changed plus & wires today.

Took it for a spin up the nearest hill and I've got the same problem.

Any other suggestions?

 

[TomB1269]

When you replaced the cam sync sensor did you replace the shaft as well?

 

[mawp]

Yes, I replaced the sensor & shaft.

The Monday after I put new plugs & wires in I was on the freeway and the CEL came on again. After a minute or so with the CEL I lost all power, I couldn't go over 30-35 MPH so I limped it to my mechanics shop and it's been there since.

He checked a few things here and there an called me back and said 2 of the 3 cat's on the Y-Pipe are plugged and I need to replace the Y-Pipe. The dealer cost is $1300 but I know the parts manager at the dealer so I can get it for $1,000 out the door.

Sucks that I live in California and we have stricter emissions here.

What I'm wondering is, why the CATs went bad in the 1st place. Would a misfire on 1 cylinder cause 2 cats to go bad? I did some research and found misfires can lead to hosing up the CAT's... I'll have to have my mechanic check the timing and make sure all the cylinders are firing before putting on the new Y-pipe.

 

[RumpRanger98]

you check the MAF ? possibly bad coil? I couldn't imagine plug cats causing a misfire? but I could be wrong.

 

[TomB1269]

you check the MAF ? possibly bad coil? I couldn't imagine plug cats causing a misfire? but I could be wrong.

RumRanger, remember our computers try to compesate for everything. If there is a problem and mix is to rich it will clog the cats, when the start clogging then you get less exhaust flow, less flow and o2's will read hi and computer will try to lean out and spark sooner feeling the load on the engine.

 

[mawp]

MAF was checked by my mechanic, it's fine.

Once I get the new CAT's he'll make sure that the coil is fine and all cylinders are firing.

 

[RumpRanger98]

RumRanger, remember our computers try to compesate for everything. If there is a problem and mix is to rich it will clog the cats, when the start clogging then you get less exhaust flow, less flow and o2's will read hi and computer will try to lean out and spark sooner feeling the load on the engine.

I understand that, but if the computer was trying to compensate for something and mix was rich. that means theres a problem that made the cats go bad............ so the original problem is not the cats, but the current problem could be cause by the cats, i guess. Cats don't normally get plugged if the motor is functioning correctly. 80k miles I dont think is enough to naturally plug the cats, so if its true your cats are causing the problem, you have an underlying problem