I have a 2004 6sp with 108K miles and over the past 2 days, I had times when I had a loss of acceleration at around 3-4K and the engine would shut off. I would not try to start it for a few minutes, and it would start up and drive, but then happen again shortly after. This only happened after I have been driving the car for 30+ minutes. After doing research on here, I am thinking it is the CAT being clogged and going to remove it and check it tomorrow. If it is clogged, I will gut it until I can get a replacement.

But one question I had, would this situation normally throw a CEL? I have not gotten a CEL. Was hoping to get one to check out the code. I changed my plugs, wires, coils about 30K miles ago, and probably will take the time to change it out at the same time.. Hopefully after the changes, this will be solved. First time I have experienced the loss of acceleration followed by engine shut down..

 

If you don't like the hassle of taking off the cat and check. You can just check and see if your cat is glowing after the drive.
If it's, then you got clogged cat.

Sometime it won't throw CEL, depends on the situation.
You can simple starts with the ignition components tho, since they are up for maintenance anyway.

 

Generally the cat will only glow if it's a HARD drive you take it for, the only way of really knowing is to physically take it off.

You say you did your coils and plugs 30k ago -if you went to stock coils again, they are probably almost ready for a change. I'd HIGHLY recommend the BHR ignition system - it is incredible. Once you get those could you should never have to worry about changing them again (and the plugs will last quite a bit longer too).

Shinka is right, it may not always throw a CEL, but even if you don't see a light, that doesn't mean it didn't throw a CEL. On a few occasions my car there a code and the only reason I found out was by actually checking it - no light had come on, but a code was thrown.

Checking and, if necessary, gutting the cat is definitely the place to start. Most likely, especially with 30k and your cat possibly being clogged, your coils and plugs should be changed too. Again, take a serious look at the BHR system (forum member Charles R Hill).

From personal experience with a clogged cat, I noticed a loss of acceleration but in higher rpms. My car never shut down like yours, so that raises a bit of concern as well. Start with the cat and let us know what it's like. I stress changing the coils and plugs, as well.

 

the cat is a little tricky, there are two bricks of material, and the o2 sensor is between them, which means the rear side can be missing/totally fail/plugged shut/ and the ecu won't see it, because its after the o2 sensor.

the hard part is that since its in the rear YOU can't see it either!

so if you pull it apart and the front side looks fine, the cat could be totally fubar in the rear.



@30k it is also time to replace spark plugs and check the ignition

 

^^ Thanks for the advise guys.

I definitely will look into the BHR. I have new plugs, coils and wires from ordering them a few months ago, so will go with that swap and then get the BHR for the next change, probably earlier this time around 20K-25K miles. I was also reading good things about the BHR midpipe, so might get that as well.

j9fd3s - if the rear side is a fail, is there no way to gut that? Or if the rear is clogged, I probably need to just replace it?

 

You can gut it lol I had to gut mine. The first half blew apart and clogged the second half. Basically just pound it out with a pole and hammer, just gotta make sure you don't hit that sensor (mine was stuck in).

It's a lot easier to gut than it sounds

 

Worked on the car today, and switched out the plugs, coils and wires to new, cleaned the MAF and since I was in there, I added an extended tube on the coolant overflow as my power steering was acting up here and there as well.

But the main thing I wanted to do, I could not. I couldnt get the Cat off the car as the bolts at the front, I just could not get off. I sprayed some lubricant, waited a few hours, tried to use my torque wrench on both sides, and nothing. I need to get it on a lift to get the leverage I need to break it loose. I am thinking of getting it to a shop and maybe just get a midpipe.

If anyone has any ideas on getting this lose, please let me know.

After I put everything back together, I drove it for about 15 min and redlined three times after warm, and the car was running smooth. No loss of acceleration yet, so I will have to see how the car reacts tomorrow.

 

Hello, I don't know what lube you used, & I'm far from an expert, but I have had good results using PB Blaster. Apply several times a few hrs apart giving time to penetrate. Good luck.

 

with the stock fasteners, the cat has pressed in studs facing forwards, and three locking nuts.

to loosen it, you take your 14mm wrench, and put it on the nut on the front side, and loosen that.

if something breaks the studs will tap out with a hammer.

 

^^ Thanks for the heads up guys. I'll get the PB blaster and apply that this week. I need to grab a 14mm ratchet wrench, was trying to find it but could not, probably lost it. So I used a socket wrench, but did not have the desired results. Hopefully this works!

 

oh BTW i was looking at my dead cat, and you can see the rear brick enough thru the O2 sensor hole, you need a flashlight. the front brick on this cat is perfect, the rear is all melty

 

hah! when they replace my cat it was completely gone. meaning there was NO material left in there. Nothing! Nada! BEAT THAT j9fd3s! lol !

 

I had the same power loss problems on mine. My car would run fine upon startup but it would continually lose more power the longer I drove it. I assumed I had a clogged cat so I completely cleaned it out. I'm still having the same problem with acceleration though. When I try to accelerate, the intake (I think), is making a gargly noise.

 

lmao! i'm trying not too! i do have two bad ones, that have perfect fronts and nonexistant rears... no CEL, but no pass the sniffer test...

 

I just thought I close the loop on this one for now. So after I switched to new plugs, wires and coils a few weeks ago, the acceleration problem has not happened again (knock on wood). I took my car to a local rotary shop (for those in SoCal, it is NeptuneSpeed, great guys) and they took off my cat as I was unable to and I did not want to strip the bolts/nuts, and after inspection, the cat was not clogged. The honeycomb was clear and on the reverse, no loose material came out after some shaking. So for me, I guess the loss of acceleration and shutdown of the engine I experience was from my bad plugs, wires, coils or a combination...

 

Odd symptom, are you driving the car under load(A/C or heater ON, radio ON)? How old is your battery, have you replaced/cleaned the injectors and fuel pump/sock filter?

 

^^ Thinking back, both of these happened at night and it has been cold recently in SoCal, I had the heater on low and radio on as well. My battery is basically new, replaced it last year summer but never replaced or cleaned the injectors or the fuel pump