my 2011 2.5 non turbo has a intermittent stall and not restart issue after a about a hour it will restart. The only code is the P0420 Cat below threshold. it gets 25 mpg in daily driving. changed O2 sensors PCV valve cleaned maf and throttle body. took it to a mechanic I trust he cant find anything. his suggestion is change the cat and see it that fixes it my question is has anyone used dorman or walker cats with success any other brands to check the subaru has 145000 miles and is a 5 speed
vaskeet
It may be the throttle position sensor developing a fault. I have full time OBD monitor (Ultragauge) installed so I would look at the idle rpm and see how that acts, especially when pulling up to a stop with a warm engine.
Could be heat soak on just about anything under the hood.
I recommend clean all your electrical connections under the hood and clean and verify all your ground connections.
I had a similar situation that ended up being the crankshaft position sensor.
Could be heat soak on just about anything under the hood.
I recommend clean all your electrical connections under the hood and clean and verify all your ground connections.
I had a similar situation that ended up being the crankshaft position sensor.
Also, check for vacuum leaks. I understand that it’s an older vehicle but I would not use aftermarket parts. Get a second and even a third opinion.
An OBD code present does not necessarily correlate as the cause of a fault in the system. Most of the time, an OBD alarm pops as a result of a fault. In the case of a stall, you will frequently see a misfire code. Well, obviously. The engine stalls and the computer says, "Hey, you've got a misfire." No kidding, huh? I saw a car that was getting a MAF code with a stall. The mechanic replaced the MAF sensor and sure enough, the stall came back. They brought the car to me and I replaced the fuel filter. "Bam! Who's your daddy, now?" No more stalls. Airflow through the MAF sensor was unusual because of the stall. In this case, the P0420 indicates a problem in the exhaust system. The only way a P0420 is going to reflect on a stall is if you have a plugged catalytic converter. More likely a misfire is occurring as result of the stall enabling the P0420 code.
A couple of troubleshooting things. If you have suspect OBD code, pull the freeze frame data and evaluate conditions at the pop. A bad catalytic converter can be checked in about 5 minutes with a warmed up engine, a back pressure gauge and a non-contact thermometer.
In this case, I would chase the stall then chase the P0420. Probably been happening for a while, anyway.
A couple of troubleshooting things. If you have suspect OBD code, pull the freeze frame data and evaluate conditions at the pop. A bad catalytic converter can be checked in about 5 minutes with a warmed up engine, a back pressure gauge and a non-contact thermometer.
In this case, I would chase the stall then chase the P0420. Probably been happening for a while, anyway.
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