Rough idle/ intermittent starting problems

[87chevyDB]

Hello all. I have a 1987’ silverado single cab king bed I’m working on. On some days the truck runs like a brand new one and on other days it won’t start at all. No rhyme or reason. Attached are the current codes I’m getting. Recent work I’ve done in hopes of resolving this issue are as follows.

Rebuilt throttle body with new injectors.
New fuel tank and sending unit
New fuel filter
New plugs
New wires
Wrapped headers
New O2 sensor with spacer ( it’s attached towards the end of the header on the driver side from previous owner, I placed spacer thinking it’s burning up from getting to hot)
All fuses under dash are in good shape
New battery
New distributor cap and ICM about 5 years ago


Thanks for any guidance in advance

 

[MarineOne]

Based on codes your getting I'd start chasing wiring harness and look for any issues. Also that 02 spacer isn't needed and could cause more issues
It's designed to run around 650 degrees.
Also the sensor should be 4-10 inches from collector where primary tubes connect

Collector gasket leak will.make it run bad too if sensor is close to that flange

 

[Ricko1966]

Those are all circuit codes,that's the only thing that bunch of codes has in common. Check the alternator for A/C ripple make sure all engine and body grounds are in place and clean.

 

[87chevyDB]

MarineOne

Just to make sure we’re on the same page. The O2 sensor is mounted on the header itself does this need to be moved Further back on the exhaust?
It being mounted there was what concerned me with over heating as I’m not educated on where it was originally located on the exhaust system since it’s all aftermarket. I just know the O2 sensor has gone out more than once. Or something else is causing that fault code.

After I replaced that O2 sensor it fired right up and ran fine. It wasn’t until a few days later that the rough idle and stalling started to occur again, as it was prior to O2 sensor replacement.

I’m at work today at the FD but I will upload some more pictures tomorrow of the exhaust and O2 sensor location after I get home. I’ll attach a photo now of the general location of the O2 sensor.

Ricko1966

Thank you for your response. I’ve replaced the main ground to the battery also but I haven’t check for corrosion in the others I will take a gander tomorrow.

Another piece of info that’s probably relevant. The truck was originally 2wd automatic and I’ve converted it to a 4speed manual 4wd. Is there a neutral safety switch that needs to be addressed that could be causing problems? Or is that issue automatically resolved within the steering column when I swapped them? I took the column out of the same truck I got the transmission/transfercase. So it’s a standard transmission model steering column. It plugged up fine to the original wiring harness in my truck.

 

[Ricko1966]

Does it crank and not start or no crank no start. Cold start the car is in open loop,oxygen sensor is not part of the equation until the engine is at operating temperature.

 

[87chevyDB]

It’s cranks but either won’t start or pops off for 5 seconds or so and dies then won’t start back is the current state.

But the day I changed the 02 sensor and wrapped the headers it cranked idled okay but almost always backfired when you started driving after making it 50 feet or so.

 

[Ricko1966]

Is your engine grounded to the negative battery lead? Do you have a chassis ground and a body ground?

 

[87chevyDB]

I believe all of those are in place but will have to confirm tomorrow.