Can a cat cause this issue?

[take a chance]

My 04 ranger edge has been havin issues with hesitating when i take off. I have noticed that it only does it now when the engine is warm. Also when idling it will randomly stutter like it is trying to stall. Originally I thought it was the a/c compressor kicking on and off but it does it with it off. Again it is random times when it happens. The list of what has been done is as follows:
New O2 sensor on bank 1, fuel injectors, purge valve, charcoal canister, map sensor, AIC, TPS, cleaned the throttle body, changed air filter, cleaned and gapped spark plugs, new fuel supply line, new fuel pump, cleaned out the intake manifold.
My question is whether or not a clogged catalytic converter would cause these issues? I think I'm down to the PCM or the cat?

 

[pjtoledo]

no.
if it revs and gets full power the cat is not clogged. chemically worn out maybe, clogged no.

any codes?

 

[rubydist]

What are the codes? There should be codes stored from the symptoms you report.

 

[19Walt93]

Get some actual diagnosis before you spend more money. Autozone's "free scan" is not diagnosis.

 

[take a chance]

Get some actual diagnosis before you spend more money. Autozone's "free scan" is not diagnosis.

I am not throwing any codes. I have a scan tool.

 

[gw33gp]

Those symptoms are similar to what happens when air is getting into the intake after the MAF. This is unmeasured air and causes erratic idle and acceleration. That is not necessarily a vacuum leak but more like an intake leak before the throttle body.

That is not a symptom of bad cats.

 

[rusty ol ranger]

You typed "AIC"...assuming you meant "IAC"? (idle air control)

If not...check/clean/replace that.

 

[ekrampitzjr]

I'm thinking intake leak too.

Is it possible there's a problem with the intake manifold during certain conditions? It's plastic, right? Maybe a pinhole or crack?

 

[take a chance]

You typed "AIC"...assuming you meant "IAC"? (idle air control)

If not...check/clean/replace that.

Yea IAC is what I meant thank you.

 

[take a chance]

I'm thinking intake leak too.

Is it possible there's a problem with the intake manifold during certain conditions? It's plastic, right? Maybe a pinhole or crack?

I'm sure it is possible. I have sprayed ether while it was running to try and identify any vacuum leaks with no change. I know that isn't a fool proof way but it is the best I have at the moment.

 

[boss3.0lranger]

Hello,
Sounds lean, maf like others stated, baro pid would be helpful also look for PVC valve fault. Wide open would bypass maf sensor readings. Hard start cold in cool weather would also trend to maf. Manual gauge of fuel pressure when see problem. Being warm engine and closed loop trend maf sensor. Disconnect maf connect sensor and run when problem is happening. If still stumbled then not maf trace fuel system and reg valve if return style two lines to fuel rail. Recent work of sncro due to sensor tells pcm number one timing and injection.
So many possible causes.

 

[take a chance]

Hello,
Sounds lean, maf like others stated, baro pid would be helpful also look for PVC valve fault. Wide open would bypass maf sensor readings. Hard start cold in cool weather would also trend to maf. Manual gauge of fuel pressure when see problem. Being warm engine and closed loop trend maf sensor. Disconnect maf connect sensor and run when problem is happening. If still stumbled then not maf trace fuel system and reg valve if return style two lines to fuel rail. Recent work of sncro due to sensor tells pcm number one timing and injection.
So many possible causes.

Thank you for info I will check those. I am not sure what "baro pid" means. You said it would be helpful.

 

[rubydist]

A sticky iac can cause those symptoms but that will almost always set a code. And just because the iac is nearly new means nothing, I have seen them no good right out of the box.

A dirty mafs can cause lean conditions but again it almost always sets a code.

 

[take a chance]

Well I finally got a code. Cylinder 1 misfire (easy right?) Changed the plugs. Still misfiring. Changed coil pack. Still there. Took the plug wire off cyl 1 and swapped it for another. Still cyl 1 misfire and added multiple random misfire code and cyl 3 misfire!! The plug wire I swapped out was #1 & #2. Any ideas? I'm stuck thinking it is pcm.

 

[rubydist]

I think I would put new wires on it, given what you just experienced.