Do you have a timing light or one of those in line spark testers? I'd check and see if I was getting spark on those two cylinders. You'll wanna clean those spark plugs up first. Use a propane torch and burn all that fouling off. This doesn't damage the plug.

Generally not a fan of Bosch spark plugs, but that shouldn't be your issue here.

Fouling can happen very quickly. Definitely within 15 miles. It would be very strange to only happen on two holes considering the parts replaced... Those should effect all 8. Have you checked the other spark plugs to see if they are perhaps also fouled to a lesser extent?

 

Swapped out plugs with the ones that were in my old heads. And. Guess what they were the same Bosch double platinums. They were fine before I did the tear down for the HG. Started the truck with the no improvement.


This won’t be much help because I cleaned off #3 before I thought to take this picture.

forgot to mention that I pulled the boot on 4 while running and got arch. There is spark.

 

I'd be tempted to try another MAF. If the running improved with unplugging the MAF I'd say it's a pretty good bet you got a defective one even if it ran better at first.

 

I still have the old one. Might swap that one in and see what happens. It was throwing a code but it was running way, way better.

I promise to get to a solution and post it.

 

several people went back to that same fuel station and the next day same fuel station was a cinder pile

 

Swapped in old MAF, no change. Checked and cleaned grounds, no change. Checked 02 loom to plug and plug to sensor for exposed wire and saw nothing. Removed and inspected intake tube from plenum to MAF, no cracks.

Something else interesting. I know a motor misfiring effects all other systems but while I was moving the truck in the driveway I had ZERO power brakes, I was standing on the pedal and was getting nothing. I did install a new break vacuum line from the booster to the plenum when I did the HG job but again I inspected it for cracks/melted areas and didn’t see anything.


What’s kind of encouraging though is it’s doing the exact same thing. I start it, it’s runs rough, climbs to 1100-1200 rpm slows and eventually does. All in 10-15 seconds.

 

No power brakes is because the engine is missing and therefore creating very little vacuum.

Do you have a way to read live data and see if any sensors are giving wonky readings? If not, a Bluetooth OBD2 dongle is about $12 at last check, and the Torque Pro app is $5 on Android. I think there are also iPhone options, but I am less familiar.

The climbing to 1200-1500 rpm sounds like a vacuum leak. Does not align with the running rich, but still a possibility. Plug of your brake booster hose and see if anything changes. If not, spray around with starting fluid while it's running and see if anywhere shows a leak.

 

Autel 619 it does live data. I am sure there is some crazy live data.

 

That'll give you a good idea what direction to look then.

 

With it misfiring as bad as it is won’t everything be completely bonkers? Fuel trim/advance all over the place I am sure but isn’t that expected when raw fuel is going into the exhaust and hitting the 02s? Not arguing that it won’t be helpful just not sure where to look and how to interpret data when the motor will not run for more than a few seconds without giving it more gas.

In the past I’ve used live data to diagnose a problem before the motor is running this poorly.