Greetings, I'm new and helping a buddy. I'm a diesel mechanic and built more than a few carb engines back in the day. Lost with how non diesel new stuff works but with a decent scanner!

1998 F150 4.6 liter.
Ugly bird poop welded true dual exhaust from a hack.

Story was after siting for a year it ran well then bad within a few drive cycles.
I saw the truck and blows white smoke from the left exhaust and relatively clean on the other.
Has what sounds like a bad miss and or mixed up 2 spark plug wires vibrates the same.
When started idle hunts up to maybe 1500 down to maybe 500 then settles roughly.

Temp reads open circuit and 118 code.
Freeze frame data shows
Fuel system bank 1 "open loop"
Bank 2 "not reported"
Fuel trim bank 1 and bank 2 both at 21.84% This was 907RPM.

I crawled under to find only 3 oxygen sensors. 1 upstream and 2 downstream. Will that work?

Total of codes:
118 coolant sensor circuit high input.
1000 OBD 2 readiness
117 coolant sensor intermittent
500 vehicle speed sensor
1352 ignition key circuit fault.

Can a coolant sensor mess up fueling badly at idle?

No misfires detected.

I plan to check intake manifold for leaks with spray.
Check plugs and holes for signs of leaks causing shorts.

Any help for a non fuel injector guy?
Does this truck report fuel pressure and I can look on autoinginuity ruling out fuel filter? Even though only one side is white smoke.

I'm a little worried that the smoke smelled more like oil than gas but my sniffer is more of a diesel smeller.

 

One more thing the exhaust only has small cherry bombs behind the factory manifolds. It has a bad exhaust leak that I just realized in my head may be before the downstream O2 sensor. As much white smoke comes from there as the tailpipe. I need to look but I can't believe that much smoke comes from a small leak unless the hack exhaust is obstructed.

 

I should ask, What are the common failures that present as misfires but don't throw codes?
I am also in the country of Panama so no parts stores with parts. Plugs maybe.

Plugs , wires, coilpacks, etc. Can they be swapped between banks to isolate if I find a cold exhaust runner or similar. It is the dual coil pack system.

 

I have a similar issue. 98 150 4.6l. The codes I get have been different every time. Misfire on 4 and 7 and 3 and 5. these cylinders are paired on different coil packs. I also am losing coolant towards the rear of the engine shown as a visible puddle under the truck. From what I have discovered scouring numerous threads is that the coolant leak is the culprit. Possibly a heater core o ring or hose leaking coolant into the 4 and 3 spark plug wells causing a short. Going to investigate more tomoro

 

all coil packs plugs and wires are new. New TPS new IAC new EGR. spray tested for vacuum leaks