I've been experiencing this problem for quite a while and cannot narrow it down to why this is happening. Basically it runs prime, up until 10 min after the engine reaches operating temp. i recently switched from ngk iridiums, to bosch +4's to ngk v-power w/ copper core, i thought maybe it was the plugs. it doesnt lose as much power w/ the v-power plugs vs the iridiums. what could it be....

 

do you have a short ram intake or cold air intake?

 

aem cold air intake

 

How hot does the engine get?? Do you see any smoke coming from the tailpipe? How's your coolant level? It could be your Thermostat isn't opening, could be your head gasket. But usually with either of those it would be running a lot hotter than normal.

Are you getting a CEL??

 

Bad o2? Usaully a bum o2 won't show up until the engine has reached operating temps... and it won't always through a CEL! My .02... HTH

Dan P.

 

hmmm............maybe it's just a tired engine?

 

my temp gauge never goes up past half way (4th gen), and theres no excessive gases coming from the exhaust. my coolent level is fine as well.
CEL??