Cat question

[steven_arias]

My 1994 Ranger has a 4.0 with the 2 catalytic converters after the y pipe. They are gutted I found out. I am dealing with a hesitation in the way the truck runs... until I floor it then all the power seems to come through. I replaced the o2 sensors and it helped a lot but it is still very noticeable. Could this be a culprit?

Thanks!

 

[19Walt93]

Hesitation meaning you step on it now and it accelerates later or it shudders and runs rough under load? If one sensor is behind the cat it would be a cat monitor which means it has OBD II and is later than a 95.

 

[rumblecloud]

On my 4.0 4by auto, both sensors are on the Y-pipe. One on either side below the exhaust manifold. Not sure about the cat query though. I know if they're blocked or partially blocked they will cause hesitation issues, but not sure about what happens if cats are gutted.

 

[RonD]

No, doesn't read like a Cat, or clogged exhaust, issue if engine runs better at WOT(wide open throttle)

The computer ignores O2 sensors at WOT, just FYI, so changing O2 sensors and having engine run better means you were/are on the right track

Clean the MAF sensor

Do you get the hesitation when REVing just in driveway, or only when driving(under load)?

Does hesitation go away when engine is cold and shows up after 4 or 5minutes, engine warm?

 

[steven_arias]

Yes it just lacks power and kind of struggles until WOT, then it straight up takes off

No hesitation while revving. Yes it does seem to start struggling once it’s warm.

I cleaned the MAF.. maybe I’ll try another one.

Thanks!

No, doesn't read like a Cat, or clogged exhaust, issue if engine runs better at WOT(wide open throttle)

The computer ignores O2 sensors at WOT, just FYI, so changing O2 sensors and having engine run better means you were/are on the right track

Clean the MAF sensor

Do you get the hesitation when REVing just in driveway, or only when driving(under load)?

Does hesitation go away when engine is cold and shows up after 4 or 5minutes, engine warm?

 

[Scott & Shari]

Are they fully gutted out? If not, a big chunk may have been left inside against the side, out of site, and was missed. It may have broken away and is now clogging the pipe. Take it off and clean it out to rule it out.