Help , my DD is messing up right before turkey day!(save me lol)

[binx]

I have an 01 autotragic mirage.

240k highway miles.

CEL is on ,

code po421 - could be catalytic converter or 02 sensor? Car goes above 70. last time I had a bad cat it wouldn't go above 30(06 envoy) car does have one problem. gas pedal gets SUPER DUPER stiff at certain speeds , it will be fine fine fine then I get to say 30mph and unless I push the shit out of the pedal no accelerating happens. it accelerates fine adn then gets uber stiff at a certain point.

any way to test the cats before spending 200 dollars on a new cat? could it be the pre-heater thingie? I heard those are expensive.

also getting po401??? I think I remember it right. EGR valve. can I just take the 2 bolts and hose off and clean it out? is this a common problem?

 

[95blackGsTurbo]

Not exactly a DSM but who cares .
P0421 - Warm Up Catalyst Efficiency Below Threshold (Bank 1)
P0401 - EGR Flow Malfunction

To sum it up your converter is going out. The P0401 is showing EGR problems because of the backpressure it is getting from the catalyst being plugged/clogged.

 

[rlacasse1]

Typically the only thing that will happen to a catalytic converter is that it will get clogged. An easy way to check if it is, is to start the car and check if you have exhaust coming out. If you have someone available have them step on the gas a little to see if the more exhaust comes out. If nothing does then it's probably a plugged cat.

 

[binx]

do you think its the CAT ? or the warm upo catalyst. bc a new manifold is teh only way to get a new warm up catalyst.

I know its not a DSM but I didnt wanna join the mirage forum

when in park no noise but in drive I can hear the plates of the cat clanging together and rattling.

 

[95blackGsTurbo]

Catalyst=Cat=Catalytic Converter it's all the same part.

 

[rlacasse1]

^^^ exactly what i thought

 

[binx]

well theres a warm up catalyst too. on the intake mani there is a mini cat thing on there. and then a catalytic converter.

 

[rlacasse1]

I have neer heard of a warm up catalyst. but if its there then its there.

or are you thinking of the EGR

 

[95blackGsTurbo]

There are 3 things that can be wrong:

Catalytic Converter Deteriorated
H02S Failed
ECM Failure

Since you hear it coming apart under the car, It would stand to reason it needs replaced.

 

[binx]

thanks for sticking with me and helping guys. REALLY appreciate it , I guess I will just take a chance and replace the cat. hopefully that helps.

 

[anmGST]

Definitly sounds like the cat, Since you say you can here it rattling.. The honey combs will break apart and clog it up.. Just get it hollowed out and run no cat ..OR find a used one at a junk yard or ebay.

 

[rlacasse1]

Pull out the CAT and use a long bar to clear out the insides of it and you will be good to go, as long as that is all that is wrong.

 

[binx]

I hope it is , Im gonna try to get one on there ASAP. will the cat being clogged ruin my motor? wont the backpressure build up and #### with my motor.

 

[rlacasse1]

no it would kill your engine before it would blow it up

 

[binx]

comforting

 

[MadBeachDSM]

An exhaust shop can test the cat for you as well. Basically they drill a hole in the cat and use some kind of tester, then they weld up the hole. Most shops test it free of charge.

 

[rlacasse1]

yeah. . so what were you saying about your throttle sticking or something. or the gas pedal not moving

nevermind just reread it

 

[binx]

it accellerates nice and gently , then finally right before it shifts it seems like it gets super stiff and I have to mash it to either accellerate or shift.

 

[rlacasse1]

Does it seem like something wrong with the tranny.

 

[binx]

no its not bucking or anything, but with 240k who knows ? I guess I will just replace the cart and see if I still throw codes or not.

 

[rlacasse1]

Its a automatic right. maybe you should try changing the fluid and filter and see if it helps. maybe the torque converter is slipping a little

 

[binx]

poked around on my lunch hour , had my neighbor take a look , he seems to think that a fresh cat will fix the
CEL because it is shaking under accelleration you just cant hear it over the motor. but its rattling to hell and he said usually this means the pieces inside or the 2 pieces that hold it together have broken and I should get a new Cat. He also said that just in case I should clean the EGR valve , I looked in my manual and EGR valve is connected with just 2 bolts and ahose on the left side of the fuel rail correct?