anyone have any issue using aftermarket bosch O2 sensor instead of factory type direct fit O2 sensor?

I'm trying to help a friend get his 88 running better, the problem its having is a rough idle and major missfire under light load, but at wot it runs fine. so far I've rebuilt the throttle body, new intake manifold gasket, plugs wires, cap rotor, cleaned the injectors, replaced the injector clips, swapped the coil, swapped the tps and temp sensors. nothing seems to make a difference so far. Sooo frustrating!

I have the entire motor injection turbo and downpipe power steering pump and fan alternator etc asking $400.00 as the sum of the parts will easily top that .   I personally heard it run and it does not knock but has a blown headgasket . Oddly enough it ran great just puked coolant when any was added. strongly believe this motor will be a good runner with a proper headgasket job . I would have repaired this myself , but decided to swap an LS1 into the car and am looking to find this motor a home

Hey all,   If it isn't one thing with this car it's another, but eventually I will have replaced everything and it'll run well for a little while (until I gotta start replacing it all over again).   Anyway, the latest problem is smoking out the exhaust once the car warms up. It smells oily, no coolant in the oil or vice versa. I pulled the plugs to get a read on them and do a compression test and this is what I found. All 4 cylinders have compression around 120 warm which is perfectly acceptable