What is your question?
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What is your question?
Sometimes it runs great, sometimes (rarely) it won’t start, sometimes (more often) it won’t give me any power when stepping on the gas. I get a 0420’code and a 0174 code. We replaced the fuel filter, a vacuum hose, cleaned the mass air flow sensor, replaced the air filter and made sure all the connections were right. After we do one thing, it seems to run great for a couple days and then starts acting up again. It acts up worse when it’s hot outside.
What makes this problem better or worse?
When the engine is hot, after we’ve driven it a while, it gets worse
How long has your 2000 GMC Jimmy had this problem?
A few months
1 Reply
P0420 is almost always due to catalytic converter ineffective performance. You could have an exhaust leak influencing the code, you could have suspect oxygen sensors influencing the code. But almost for sure the catalytic converter (bank 1) is at fault for premature wear out -- perhaps likely caused by other vehicle performance concerns, such as fuel consumption issues causing catalyst over-temperature. The P0174 code does indicate "lean" fuel conditions that would lead to increased fuel into the engine, and in turn - into the exhaust. Hands on inspection and diagnostic testing is needed. Use this link to find some shops near you that can help with your concern: www.repairpal.com/repair-shops