I have a 2003 Subaru Impreza Outback Sport with 73,xxx on it. Recently, it has started to hesitate badly while accelerating and will not go faster than 50 mph. 

 

I took it to the local dealer, who wants to charge $2,300 to replace the catalytic converter and front o2 sensor, saying it was plugged...but it hasn't been glowing red hot.  The check engine light is on (not flashing) 

 

I already replaced the catalytic converter, front o2 sensor, ignition coil, spark plug wires, spark plugs and the valve gaskets (oil came out when I pulled the spark plug cables) a couple months ago. 

 

The engine runs more smoothly with this more recent set of problems compared to when I first replaced the catalytic converter a few months ago.  The catalytic converter would turn red hot then, which is why I replaced it. 

 

Any thoughts on what could be causing this problem? My apologies if this has been covered before on here...I'm new to the forum. 

there may be a vacuum test that would help determine if there's exhaust blockage.

 

if it wasn't done, the car is way overdue for a timing belt service - 105 MONTHS or 105K. maybe it slipped a tooth already?

There are many things that can be at fault, but first RUN from that dealer.

 

RUN FASTER!

 

Now that thats cleared up, stop replacing parts.

 

a 2nd cat ?!?!?!?!

 

Lets do first thing first, get the codes read and post the actual code here. Exhaust systems do get hot, cats get red hot, thats how they work at times.

 

Whats the history on this car?

I've had it for a little more than two years and bought it from the original owner with 45,000 miles on it. Hadn't had any major problems with it. I replaced the ignition coil about six months after I got it. After changing the air filter a couple months ago, the cat turned red hot and the mechanic I took it to (not the dealer) said it needed to be replaced. I'd already swapped out the front O2 sensor on it and that didn't fix the problem (replaced it with a Denso O2 sensor I got at AutoZone).  After the problem (red hot cat) came back, I took it back to that mechanic, who replaced the ignition coil (second one I've replaced on it.) After he did that, I also put on new spark plug cables and replaced the plugs.

 

About a month passed and the CEL turned on and would go off, before it would just stay on for the past few weeks. I went out of town for a week and when I came back, the CEL remained on, but the acceleration performance significantly reduced over a couple of days -- from being able to go 75 on the highway to struggling to maintain going 50, with jerky acceleration and shifting. 

 

Not sure if it could be as simple as the PCV valve or the knock sensor, but those are the next two things I'm considering swapping out (myself.) 

 

 

 

 

There are many things that can be at fault, but first RUN from that dealer.

 

RUN FASTER!

 

Now that thats cleared up, stop replacing parts.

 

a 2nd cat ?!?!?!?!

 

Lets do first thing first, get the codes read and post the actual code here. Exhaust systems do get hot, cats get red hot, thats how they work at times.

 

Whats the history on this car?