The trucks a 97 1500 5.9 magnum, on the 21st I blew a head gasket. Blew out on cylinder 8 in between the cylinder and push rod valley, it dumped oil into the cylinder. I shut it off immediately once it blew, It was ran to get it on & off the trailer, then into the shop. Tore it down, inspected everything. Apon visual inspection everything was fine, the heads were cleaned, re-surfaced & I made sure the valves weren’t leaking at the seats. Cleaned everything up, put the heads on with a new set of MLS gaskets, new intake manifold gaskets, valve cover gaskets, plugs, wires & exhaust manifold gaskets. Well I started the truck, let the gaskets break in. It sounded healthy at idle along a slite blip of the throttle (maybe 1,500 rpm) well first drive it just spits and sputters “under load” wouldn’t get above 2500 rpm’s & I couldn’t go more then maybe a quarter throttle without it just wanting to stall out almost like it’s loosing fuel. Was throwing code for loss of crank or cam position sensor, bought new pick up coil & crank sensor. It ended up getting the code to go away but still wouldn’t drive right. Can’t go above quarter throttle still, but I can get to 3,000 rpm before it spits & sputters. In total since it was all done Its got new
Head gaskets
Intake manifold gaskets
Valve cover gaskets
Exhaust manifold gaskets
Crank position sensor
Pick up coil
Cap & rotor
Spark plugs
Spark plug wires
Upstream o2 sensor
Throttle position sensor
Fuel sync set to +1
Motors in time
Everything was torqued to spec and in the proper sequence, I know the truck well but I’m currently stumped. If anyone has some insight that’d be awesome.

 

If it burned a lot of oil/coolant, it's possible the cat is roached. Remove the front O2 sensor, and go for a drive, does it run better?

I would also be inclined to put the old crank sensor back in.... the aftermarket sensors just don't work well in these trucks.

 

So the truck actually dosent have a cat, hasn’t for I wanna say 3 years now. There was no contents left so I put a 2.5” magna flow x-pipe in its place, only time an issue arises is when the o2 or another sensor ****s the bed. I haven’t tried to drive it with it unplugged yet though, I’m leaning towards the o2 sensor as when the truck was an automatic it would do exactly what it’s currently doing the two times it went out. Plus the trucks being really talkative as it’s running real rich.

If I knew where it ended up at I definitely would do so, have had three new sensors be bad since I replaced everything

 

Your truck has two temp sensors, a one-wire sensor for the gauge in the dash, and a two wire sensor for the PCM. On my 96, the two wire sensor was cleverly concealed to the drivers side of the thermostat housing, almost under the a/c compressor..... Without that sensor, the PCM will think the engine is -40 degrees, and positively DUMP fuel in order to get a burnable mixture.

 

Clogged cat could be a possibility but typically causes less of spit and spatter and more of a "constipated" reaction. Look at your O2 sensor readings, if it goes lean at higher RPM you have indeed a fuel issue.

HeyYou makes a good point too. What does the PCM think the coolant temp is ?

 

If I plug the code reader in, go to live data it’s reading at 174

 

I’ve been thinking about unplugging it just to see if it would quit leaning it out and I could have my rpm range and drivability of the truck back. It’s dumping fuel but then leans out, almost like it’s got a hard fuel cut set

 

Unplugging it won't help..... Try unplugging the front O2 sensor, see if it runs any better.