Problem with my 3.0

[uscfootball27]

Hi guys

My 2000 Mazda B3000, started out having problems with vacuum leaks, we fixed that problem, then it progressed into a misfire at cylinder 2(check engine light) then progressed into a misfire at cylinder 5, we've replaced the coil pack, the plug wires, and spark plugs? What else could be wrong? I've heard rumor of a cracked head can cause symptoms, like this. I really hope its not that. Hit me with any and all ideas that might help! I might be taking her(my truck) down to a shop on Monday, but would rather fix it on my own. Thanks!!

-Keith

 

[oachs83]

spray starting fluid all around the intake gaskets while running. If the rpm's pick up that is telling you have a gasket leak. These are common for that.

 

[ForOffRoadDriving]

good old starting fluid, thats where id start too.

 

[Runnin'OnEmpty]

Hi guys

My 2000 Mazda B3000, started out having problems with vacuum leaks, we fixed that problem, then it progressed into a misfire at cylinder 2(check engine light) then progressed into a misfire at cylinder 5, we've replaced the coil pack, the plug wires, and spark plugs? What else could be wrong? I've heard rumor of a cracked head can cause symptoms, like this. I really hope its not that. Hit me with any and all ideas that might help! I might be taking her(my truck) down to a shop on Monday, but would rather fix it on my own. Thanks!!

-Keith

Both cylinders #2 and #5 are the center ones on
each head, so it's unlikely that both heads are
cracked.

I'm betting it's a leaking manifold gasket, or maybe the center
manifold bolts have loosened up........?

 

[uscfootball27]

Thanks for the starting fluid suggestion guys! But, sadly it also didn't work. We are going to try a pressure test tomorrow, and if that doesn't work. I think we're stuck with our automotive supplies.

-Keith

 

[evanesce69]

I've read here in the forums about fuel injectors going bad. I dunno if that would cause the misfire codes though.

From my own experience, lean mixtures, AKA vacuum leaks can cause preignition that could burn an exhaust valve or two. I've posted a couple of pics of MY burnt valves in the 3.0L forum somewhere....

Hey, just two ideas is a sea of plenty....




Rob

 

[uscfootball27]

Thanks for the info mate!

-Keith

 

[oachs83]

To bad it's never that easy. Did you use a straw on the starting fluid and get right down to spray where the gasket mating surface is ALL AROUND? Because on the upper intake the ports that feed the #2 and #5 cylinder share the same gasket.