OBD II codes on '96 C1500

Hello there, this is my first post so I apologize if this has already been covered.

I recently had to replace the intake manifold gaskets due to the infamous Dex-Cool coolant issue. Everything was put back together correctly. When starting the vehicle, it ran fine and thank God, the leaking had stopped, but once warmed up, it started idling pretty bad. Not enough to stall, but shake nonetheless.

The motor (350V8) had very little power and of course, not too long afterwards, the "Check Engine Soon" light came on.

I had the codes scanned and it came back with:

PO300, Engine Misfire Detected
P1153, Insufficient Switching Bank 2 Sensor1

I should also add that a month prior to the manifold repair, I replaced all 4 oxygen sensors with new Bosch units to solve yet another "Check Engine Soon" porblem.

I was certain to re-install the distributor in the exact location (also replaced the cap and rotor). Would pulling the ECM fuse set everything to baseline again?

Any insights/help would be appreciated.

RPG

I would look at the misfire code first (p0300)
Since it occurred after you had been working on the engine, I would go back and check your work (don't take that as an insult)...sometimes you will find that you crossed plug wires or left something unplugged.
Clearing the codes will not fix the problem...you have to find out what is at fault first.

thanks Merlin for the reply. 1996 Chevy C1500, 350V8, 98k miles. Auto trans. No insult taken. I went back and checked every connection I removed as well as the spark plug wires and routing.

In the last week, I've done the following:

Replace all 4 oxygen sensors due to another error code prior to replacing the manifold gaskets. MIL light ON. A day after the sensors were replaced the light went out on its own. (that's good I think)

A few days later, replace the intake manifold gaskets because they were leaking anti freeze.

Replaced the distributor cap, rotor, plug wires and spark plugs. (because of the mileage)

When I re-installed the distributor, I was careful to put it back exactly where it was. (ever mindful that it is really a camshaft position sensor)

Removed both the ECM fuses,waited 10 minutes and then replaced.

The motor seems to be running very, very rich. There is black, sooty stuff on the garage floor after the condensation has evaporated from the exhaust. And at idle, it shakes pretty bad but will not stall. (I guess that's a good thing)

I'm scheduled to take the truck in Monday to the dealer, but would like to avoid that if at all possible.

One of the guys at the local Auto Parts store said to remove both the ECM fuses (see above) wait ten minutes, re-install and then take it for a 10 mile drive not exceeding 35mph. I assume this would re-calibrate things because the battery was removed for the intake manifold gaskets repair???

Your thoughts are appreciated.

RPG

I had a mechanic look at it and he found that the #4 injector was not spraying. He also did a complete throttle body cleaning, replaced the fuel filter, and the first right side O2 sensor.

Runs perfect now.

thanks for your help,

rpg