2009 Ram just rebuilt 5.7. Crank it kinda starts if you rev it and dies under 800RPM.

[radmanptr]

Installed my rebuilt 5.7 engine last week. Ive replaced all the sensors crank, cam, oil temp, oil pressure. Even did the Throttle body today.
It will fire and if you milk it up you can get it to run pretty decent at 3-4000 RPMs let off gas and you can REALLY hear the misses kick in and it will die.
The #7 and #8 have the most misses 125 - 95 on both cylinders. The others 2-6 misses. Nothing like the 7 & 8 cylinder. Fuel pressure is good, oil pressure is good.

Today I got code P0175 fuel system 2/1 rich and P2096 = downstream fuel trim system 1 lean
Tried Iridium plugs Then copper.
Ive flopped the coils around dosent eliminate the miss. 7 & 8 still have 100s of misses and are black and sooty.
What would cause 7 & 8 to constantly miss fire?
NOW what to do? Any other suggestions are welcome Thanks Kevin

 

[jws123]

pull the valve covers and make sure the rockers are moving on those cylinders its common on almost every camshaft job to miss the holes for the push rods due to the angle they are on.

 

[radmanptr]

Thanks. I’ll look at the. Pushrods.
Update : getting 200 to 300 misfires on cylinder 7 & 8

 

[EdGs]

Did you replace sensors because of the codes?

Did you use OEM sensors from a reputable source (NOT AMAZON OR EBAY)??

Where were the plugs from?

Is it showing any other codes besides P0307 and P0308, P0175, and P2096?

Is it the same as before replacing all those sensors?

 

[radmanptr]

I didnt get a lot of the sensors back from the builder. crank sensor, cam sensor was busted off. and while we were throwing money at it i bought a new throttlebody.
but 7 & 8 seem to be missing hard and 2-300 times each

 

[EdGs]

So, it hasn't run right since the build?

Should be the builders baby until it's right.

 

[radmanptr]

Yeah thats next. He built it I put it in and trying to get it started.

 

[radmanptr]

Took the drivers side valvecover off and #7 intake was not moving. So the builder sent a guy over and we pulled the head and replaced the lifter and everything worked out and runs great. Dont understand why the lifter didnt pump up but works great now.
Thanks for the input.

 

[EdGs]

Awesome! Glad the builder stepped up and got it sorted.

#8 misfires cleared up too?

Sh*t happens sometimes. I know you're relieved.

Happy Ramming!