Roberts2500HD

Under heavy load ( in park with it rev’d to 3k rpm it’s at 43psi . So I’m guessing with a new pump it should stop the random missfires above 2k rpm .. probably why it’s missing cause it isn’t getting enough gas

Just did Fuel compression test : with truck key turned over but not started about 53 psi , with the truck started it dropped down to about 48psi . With engine in park and rev’d to 2500 it went down to about 43 or 45 psi

I put new sensor on drive side cause the only code for 02 sensor was Bank 1 Sensor 1

I can’t seem to get the truck to throw a code for a cylinder.. it’s just saying random misfire P0300 .. and when pulling plugs only drive side looks bad . I’m going to do a pressure test soon when I find a place to do it . No local stores have one for sale .

Well driver side I haven’t replaced due to it wasn’t leaking no where near as bad as the passenger. But 3 bolts hold the manifold on driver side . But it doesn’t really have a leak

So I bought a truck 02 GMC Sierra 2500HD and it had a bad manifold leak ( common on the 6.0L ) Sluggish on take off & blinking engine light at 2000rpm . Bad smell coming from exhaust when idling and driving Codes : P0174 , P0300 Next Day NEW : Manifolds + Gaskets EGR Valve & Tubes+Bracket Plug , Wires Intake Gasket / Cleaned Injectors Fuel Filter Wanted To check plugs after a day of doing that . Bank 1 plugs ( all 4 ) was burnt/corroded . They was black not oil black . Did research on it .. most people said it’s your 02 sensor Then I changed the 02 on that side and it gained little more power .. but still missed fire above 2000rpm Called GM 8/3/2020 . Then say 8 out of 10 it’s then cam sensor Changed Cam Sensor and it sound smother and has even more power but still miss fires at 2000 rpm or more . please help with what it could be I’m exhausted with it should I do a CASE relearn?