P0300 on 6.0l HELP!!
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P0300 on 6.0l HELP!! ok , this is my first post here...i have a 2002 chevy 2500hd with a 6.0l true dual flowmaster 40's k&N in the stock box ( with a pvc intake tube )
heres my symptoms:
-rough idle
-p0300 code only ( comes up above 2400rpms only )
-poor fuel mileage
-shakes prettybad on highway ( hops around town ) and the driveline is all mint and tires are balanced properly
-i really have to get on the throttle to go any where
-exhaust note is nice and snappy when the engine is cold but once it warms up it starts " poping" and sounding like $hit ( noe leaks either )
What ive done ( using 3 of my gm certified buddys ideas and my own )
*new plugs/ wire per gm spec
*coils tested and all are good
*new fuel pressure regulator
*8 new balanced injectors ( mine were junk )
*new fuel pump ( mine was failing )
*new updated green intake gasket
*fuel filter
*cant find any craked vacuum lines either
* checked for broken valve springs and none present
*compression is 175 lbs on all 8 cylinders
*2 new rear O2 sensors that were bad
*fixed broken power wire on EGR
re set pcm too
heres my thought, i think i have a pluged or melted cat ! bank 1 cat gets hotter twice as fast as bank 2 does my LTFT2 is higher all the time by 1-2% than LTFT1
O2 readings (taken when engine was driven for 1hr and at idle )
B1S1 -.2-.88
B1S2- .2-.288 ( this sensor is new )
this cat was running alot hotter
B2S1- .2-.80
B2S2- .1-.6
heres my symptoms:
-rough idle
-p0300 code only ( comes up above 2400rpms only )
-poor fuel mileage
-shakes prettybad on highway ( hops around town ) and the driveline is all mint and tires are balanced properly
-i really have to get on the throttle to go any where
-exhaust note is nice and snappy when the engine is cold but once it warms up it starts " poping" and sounding like $hit ( noe leaks either )
What ive done ( using 3 of my gm certified buddys ideas and my own )
*new plugs/ wire per gm spec
*coils tested and all are good
*new fuel pressure regulator
*8 new balanced injectors ( mine were junk )
*new fuel pump ( mine was failing )
*new updated green intake gasket
*fuel filter
*cant find any craked vacuum lines either
* checked for broken valve springs and none present
*compression is 175 lbs on all 8 cylinders
*2 new rear O2 sensors that were bad
*fixed broken power wire on EGR
re set pcm too
heres my thought, i think i have a pluged or melted cat ! bank 1 cat gets hotter twice as fast as bank 2 does my LTFT2 is higher all the time by 1-2% than LTFT1
O2 readings (taken when engine was driven for 1hr and at idle )
B1S1 -.2-.88
B1S2- .2-.288 ( this sensor is new )
this cat was running alot hotter
B2S1- .2-.80
B2S2- .1-.6
Thread Starter
Teching In
Joined: Apr 2010
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oh, and i forgot to metion i can only get it to rev out to 4500rpms..fuel pressure is 53lbs ( static ) 51lbs idle and gos to 62 when i raise to 2k rpms seems more and more like my malfunctioning egr ( since fixed ) was causing a misfire that destroyed my cats and i still have themiss
get a cheap vacuum gauge and hook it up. if vacuum drops at 2k rpm's, the cats are clogged.
also check your MAF and MAP sensors. make sure no air is leaking in downstream of the MAF. idk if you have access to a good code reader, but thats really the only easy way to check out the MAP.
also check your MAF and MAP sensors. make sure no air is leaking in downstream of the MAF. idk if you have access to a good code reader, but thats really the only easy way to check out the MAP.
what mods?
and hoestly, if its not an HCI car, i have no idea what it should be. hahaha. maybe google some specs. does that MAP reading go down at 2k rpms? hold it for 10-20 secods or so. MAP=compooterized vacuum gauge.
and hoestly, if its not an HCI car, i have no idea what it should be. hahaha. maybe google some specs. does that MAP reading go down at 2k rpms? hold it for 10-20 secods or so. MAP=compooterized vacuum gauge.
Thread Starter
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my buddys 5.3l MAP reading gos up when throttle is opened up so i think its time for some magnaflow cats
which cat is more likely to be bad the one that gets the hottest i assume cause the internals would melt from a rich condition
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