4.0 popping and shooting flames

[89danger_ranger]

I have 93 ranger 4.0l
when driving whith half throttle it misses and has no power
but then under full throttle it will run perfectly fine
now under deceleration around 2000 rpms it will pop real loud every once in awhile
then while reving to 2000 also it will pop real loud and shoot flames out the exhuast

The check engine light is not on all the time only sometimes while driving it will come on then go off
I was thinking plugs, wires
any suggestions what to do?

 

[Quartermile]

Sounds like your exhaust system is plugged, and most likely the catalytic converter. It has this honeycomb looking stuff in it, and that gets plugged sometimes. You can take a pipe and knock it out (and make it "illegal" for road use) or replace it (with another cat . . . . .or pipe)

 

[bcost882]

throttle position sensor possibly

 

[Nhaz]

Sounds like the cats are plugged up. Without destroying them give them a couple good whacks with a hammer. It MAY knock some crap loose and clear it out some. I would do it while its running too so you can see the crap pop out the pipe and know you have done it... or not =>

Don't Beat on it though. the object is to knock the crap loose not break the internals of the cat.

Also running on the highway hard for a few minutes may pop the crap loose as well. (assuming the vehicle co-operates).

If not I would say the cats are damaged or dead.

 

[1994Rangerxlt]

i just had this problem my cats are empty.. it was my o2 sensor.. and correctly me if im wrong. if cats are colgged how would flames be gettin threw?? wouldnt they stop flames

 

[89danger_ranger]

Thanks I'll check the cats

 

[Ranger44]

You can easily check for exhaust restriction using a vacuum gauge.

Normally an engine will run closer to 20 in. hg.

When you blip the throttle it should go down closer to zero, then pop back up to where it was before. If it hangs out at about half of what it was, then goes back, then the exhaust system is restricted.

And, please....don't listen to these people. Check it the proper way and replace the proper exhaust pieces.

You'd have to understand though......that if it is your catalytic converters that are clogged....there has to be a reason. Too much fuel, oil, or coolant contamination(especially a overly rich mixture) in the exhaust will damage an Oxygen sensor and catalytic converter. So check for the root cause.

 

[1994Rangerxlt]

cats are empty. i changed o2 sensors then it worked. then messed up then i switched the wires around from one o2 to another. and it worked