Intermittent misfires rough idle and acceleration

[fenderville]

I have a 2000 Ford Ranger 4.0 Extended Cab 4x4 off-road.

About three weeks ago, the engine light came on so I stopped by AutoZone to pull the codes.

It was a misfire on bank 6. So, I changed out the plug and all was fine... for a few weeks.

Then, the rough running came back and engine light came back on. So, I took it back to pull the new codes and now there is a misfire on bank 3 and 4.

Last year I had the intake gasket fixed because I know the 2000 Ranger 4.0 is notorious for blowing intake and manifold gaskets. It ran great for 10 Months now the misfires. They also did a smoke test and fixed any vacuum leaks. And replaced the exause sensor on the passengers side.

My first thought was that the plug was fouled because when I replaced bank 6 all was well for a few weeks. But, now 3 and 4 are misfiring and it is sort of intermittent. It runs fine for a few miles then rough for a while.

I hate to just start throwing parts at it but I am at a loss.

Any help would be greatly appreciated!

 

[fenderville]

I am still at a loss. I reset the codes and now I get a miss fire on bank 3 and 4. They are not close so i ruled out a gasket leak. Any thoughts?

 

[enjr44]

Well, when was the last time you did a complete tune-up? You know like plugs and wires. What kind of plugs are in there? If not motorcraft double platinum, that may be your problem. Those 4.0s eat just about anything else in short order.

 

[Lone-Ranger]

^^ditto. You should never swap out just one plug anyway.

 

[JimRummy]

You guys know where you can get motorcraft double platinums? I can only find singles for a 93 4.0.

 

[fenderville]

Thanks for the replies. The plugs and wires are not that old, less than two years. That is why I thought it was ok to change just one plug. I put motor craft platinums in.

 

[CountryBoy704]

I put motorcraft something in mine maybe 3 months ago and already getting a noticeable miss until the engine warms up