Hi there,
Thanks in advance for any info. I have a 2007 Toyota Prius, 176k. I moved to Seattle from NYC and noticed it seems to be losing power going up hills and just in general. I got a check engine light shortly after I noticed this and it said my catalytic converter was gummed up, I thought that would be it, changed it...still lack of power and then got another check engine and it was a misfire on cylinder 4. I changed the plugs and packs. Still continued, i moved the plugs and packs around and the misfire did not chase, still on 4. I cleaned the throttle body, the mass airflow sensor, changed injectors, still a misfire on 4.
I took it to my mechanic and he replayed everything I did and said he could only know by taking everything out and disassembling it and it would be a base cost of about 3k.... any ideas a nominally capable person such as myself could try?
Further, the misfire has now made the car chug and shake when idling and deaccelerating into a stop and idle, which I moderate by letting off the brake a little as I am coming into the stop - not sure why that works...but it does.
Thanks in advance for any suggestions
I got a check engine light shortly after I noticed this and it said my catalytic converter was gummed up
There is no such thing. Codes associated with the check engine light point to conditions that can have many different causes. They rarely if ever tell you what specific part is at fault, you need to do diagnostics to determine that.
Your old catalytic converter was in all likelihood perfectly good, though it would have no doubt been damaged by the misfire after a while. Your new converter will be toast if you continue to drive the car in that condition.
Have you checked live data for any clues?
I took it to my mechanic and he replayed everything I did and said he could only know by taking everything out and disassembling it and it would be a base cost of about 3k...
You need to find a different mechanic who can do a proper diagnosis using a high-level scan tool.
any ideas a nominally capable person such as myself could try?
Vacuum leaks are pretty easy to check for. There are diagnostic tips in the troubleshooting section of the FAQ. You might want to do a compression check to verify internal engine condition, after all the car is 17 years old.
1) Catalytic converter - my 'mechanic' said that the check engine light pointed to the cat. he showed me the old one and produced a lot of debris when he banged it on the ground. i have no doubt that it was shot or close to it, but i don't think that's the cause of the new check engine light misfire on cyl 4. - I don't have anything to check live data. I'm just a guy with a socket wrench who is learning and doing what I can - is it worth investing in?
2) - I definitely need a new mechanic - agree
3 - compression check said compression is fine.
1) Catalytic converter - my 'mechanic' said that the check engine light pointed to the cat. he showed me the old one and produced a lot of debris when he banged it on the ground.
Checking the converter with a back pressure gauge would have revealed whether it was causing engine performance problems. The trouble with replacing the catalytic converter before fixing the engine problems is now the new converter is at risk of being damaged.
I don't have anything to check live data.
You really need an OBD2 scanner to work on modern cars. These days even inexpensive scan tools can display live data, many can record and graph it. Even basic information like fuel trims can be very helpful and you can check sensor outputs for problems. There are recommendations for scan tools at various price levels in the FAQ.
If you have a specific code(s) from a scan tool, we may be able to guide you in the right direction.
Without knowing too much more, one other thing to check is the health or charge of the hybrid battery. I’ve gotten a misfire code when the battery wasn’t charged up or was sitting for a while.
