Huge smoke cloud

[Kubaner]

I’ve got a 1996 Tahoe with 155k on it.
Had a few days where it would stall immediately after putting it in drive after a cold start up.
After restarting it would run fine.
Was on the highway for about a half hour Sunday, doing 85 mph at around 3000 rpm. Felt a stutter and saw the tach jumping around. Looked in the rear view and there was a cloud behind me I couldn’t even see through. Pulled over. Checked it over to see if any coolant loss or anything obvious. Drove about 30 miles home at 50 and had no problems.
Revs fine and seems to run normal now. The back of the truck was coated with burnt oil. Doesn’t seem to be coolant related. One of the cats looks fried and had suspected it to have maybe been somewhat clogged. Heard mention of a leaking injector rail that could be losing fuel into the intake, but not sure what caused this.
Any insight would be really appreciated.

 

[Hoesgottaeat2]

Do a compression test. Start on the side of the engine you suspect the clogged cat. If it’s oil you see on the back of the truck, it may be getting past a ring or rings.

 

[Joseph Garcia]

Welcome to the Forum from NH.

Lots of knowledgeable folks here who freely share their knowledge, experiences, and perspectives. Knowledge is power.

I hope that you will become a participating member in the Forum's discussions.

Pics of the truck, please.

You are already receiving sage advice from the knowledgeable folks on this Forum.

 

[Miami-Dade]

I’ve got a 1996 Tahoe with 155k on it.
Had a few days where it would stall immediately after putting it in drive after a cold start up.
After restarting it would run fine.
Was on the highway for about a half hour Sunday, doing 85 mph at around 3000 rpm. Felt a stutter and saw the tach jumping around. Looked in the rear view and there was a cloud behind me I couldn’t even see through. Pulled over. Checked it over to see if any coolant loss or anything obvious. Drove about 30 miles home at 50 and had no problems.
Revs fine and seems to run normal now. The back of the truck was coated with burnt oil. Doesn’t seem to be coolant related. One of the cats looks fried and had suspected it to have maybe been somewhat clogged. Heard mention of a leaking injector rail that could be losing fuel into the intake, but not sure what caused this.
Any insight would be really appreciated.

Welcome from Miami&NYC!

Moved you here.

 

[Eman85]

Burnt oil?? Did you check the oil level? If oil is going through the motor and burning it has to go through a cylinder. pull the spark plugs and look at them, oil will be on the tips and they will be black. As stated do a compression test especially if it's one cylinder. Don't go off of the rails chasing what someone once said, do the diagnostics. With the engine running remove the PCV valve and put your finger on the hole and see if you feel pressure or suction. Does anything come out of the hole with the engine running?
Does it smoke at all while it's running now? Did the oil level drop? Don't know how you are seeing a cat as being "fried". If you suspect a clogged cat you can easily test with a vacum gauge that has a low pressure section on it for mechanical fuel pumps.