help!! p0300 misfire, tps fault, bank 1 and 2 lean fuel trims...

xps800doo

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july of 21 purchased a 08 with 170,***. seemed fine had a rough idle never put a scanner on it to look at anything, then started throwing a throttle body circuit a fault, ordered a oem throttle body sensor new plugs and wire just because, put them on the shelf for then I have time. 12/21 flashing check engine light along with stabilitrac and traction control lights. put the scanner on it and strong #6 misfire, pull valve cover rocker loose.... tore into it. replaced all rockers, trays, had heads gone through, new VLOM, new oil pressure sensor....now i am getting a cyl 1 & 7 misfire at idle only, as soon as you raise it to above 800 rpm the misfire goes away. getting a p0300 misfire still getting the throttle body sensor fault, bank 1 and 2 fuel trim lean fault. and low oil pressure fault.

the gauge was at 40 almost all the time before #6 failure, now it will go to 40 at start up and after a few seconds drop all the way to 0. Rev up engine and it will come back a little… don’t have a pressure gauge, but there is some oil there, been driving it a week now .

Tried the carb clean spray trick around the intake and injectors and that doesn’t seem to change anything.

Where does one go from here!?
 

Doubeleive

Wes
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oil pressure is probably the pickup tube o-ring, very common
have you cleaned or checked the maf?
 

AmunRoo

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You should try a leak down test on the cylinders. Have you tried a compression test yet?
 

Foggy

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Common for #6 to misfire the most when plugs/wires are going bad..
Replace that easy stuff first.... then go deeper if it doesn't help..
Just went thru this with a 1500 that only had 30K on the plugs and wires
 

Russ

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My first concern would be to verify proper oil pressure. Have you inspected the screen under the pressure sending unit?
 

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