View Single Post
Old 11-22-2021, 06:40 PM   #7
fdryer
Super Member
fdryer has a reputation beyond reputefdryer has a reputation beyond reputefdryer has a reputation beyond reputefdryer has a reputation beyond reputefdryer has a reputation beyond reputefdryer has a reputation beyond reputefdryer has a reputation beyond reputefdryer has a reputation beyond reputefdryer has a reputation beyond reputefdryer has a reputation beyond reputefdryer has a reputation beyond repute
 
fdryer's Avatar
 
Join Date: Jan 2006
Location: NYC
Posts: 45,747
 

2003 L-Series 3.0L Sedan
Default Re: Strange P0300 occurrence

Unless that gas station makes the news headlines of dispensing contaminated gasoline to every vehicle filling their tanks, it's not likely only your tank to have contaminated fuel.

Catalytic converters don't last forever and often disintegrate internally to choke exhaust flow. The infrequent problems of catcons can create unusual and erratic engine running problems.The easiest test for a damaged catcon are banging it and listen for loose cat guts and/or removing the exhaust manifold O2 sensor for a brief drive.

Banging catcons should not result in rattling of the internals. Removing the upstream O2 sensor for an alternate exhaust path can reveal either the same symptoms or sudden improvement in engine running at idle and during a short drive with a loud exhaust sound. Allowing the exhaust an alternate exit before a suspected blocked catcon should restore engine performance almost immediately. A soup can diverter on the sensor bung might be needed to direct hot exhaust away from plastic parts nearby during a brief drive around the block. Either the engine suddenly performs better or not.
fdryer is offline   Reply With Quote