I've been dealing with these random issues for a few days now. Last night I spent a ton of time rewiring stuff, checking everything, reset the ecu and it ran fine for about 30 miles.

P0104 Mass air flow (MAF) sensor/volume air flow (VAF) sensor �“ circuit intermittent Wiring, poor connection, MAF/VAF sensor, ECM
P0300 Random/multiple cylinder(s) �“ misfire detected Spark plug(s), HT lead(s), injector(s), ignition coil(s),low compression, wiring
P0301 Cylinder 1 �“ misfire detected Engine mechanical fault, wiring, ignitiion/fuel system, injector, ECT/MAF sensor, ECM
P0302 Cylinder 2 �“ misfire detected Engine mechanical fault, wiring, ignitiion/fuel system, injector, ECT/MAF sensor, ECM
P0303 Cylinder 3 �“ misfire detected Engine mechanical fault, wiring, ignitiion/fuel system, injector, ECT/MAF sensor, ECM
P0304 Cylinder 4 �“ misfire detected Engine mechanical fault, wiring, ignitiion/fuel system, injector, ECT/MAF sensor, ECM
P0136 Heated oxygen sensor (HO2S) 2, bank 1 �“ circuit malfunction Heating inoperative, wiring, HO2S, ECM Oxygen sensor (O2S) 2, bank 1 �“ circuit malfunction Wiring, O2S, ECM
P0141 Heated oxygen sensor (HO2S) 2, bank 1, heater control �“ circuit malfunction Wiring, HO2S, ECM

The story:
I was getting P0136 and P0141, so I replaced the rear o2 sensor.
Then I got P0104, performed wiggle test on MAF sensor and failed. Rewired MAF sensor.
Reset the ECU, car runs and drives fine. 30 miles down the road, starts misfiring. Pulled over and checked the codes: P0300, P0301, P0302, P0304. Had to drive home, so I continued driving. Car would go through periods where it would seem fine, then would misfire again. Idle bounces between 1-3k.
Checked codes when I got home, P0300, P0301, P0302, P0136 (back again)
Waited awhile, drove around the block, checked codes again. P0300, P0301, P0302 (P0136 is gone again)

I've been suspecting TPS for awhile now because I've been dealing with a weird idle issue since before all this misfire business (although that could have been the MAF as well I guess, but now the MAF is fixed and the idle issue is still there and way worse), but I don't think a bad TPS could cause all of this. Plus, I just replaced the TPS with a used one I bought off of here, so unless both of them are bad (they are both KEFICO)..

I have replaced the MAF wiring, TPS, and both o2 sensors (while I was inspecting this before I noticed one of the heater wires to the front o2 sensor was broken, that was the very first thing I did before any of this).
EDIT: Does anyone know why P0136 would keep coming back and going away? Are both of our o2 sensors the same? They have different part #s, but I'm pretty sure the Bosch universal sensors are the same. I replaced both of mine with the same sensor - that shouldn't cause any issues should it?

I also recently replaced my wires with PRDs a few months ago, so unless I got a bad set of wires from them I don't think that could be the problem.
EDIT: I just had a memory of reading a post where someone said they got a set of faulty PRD wires, can anyone remember this or did I just imagine it?

I'm going to check the plugs next, but those were replaced about a year and a half ago with NGK Iridiums (Platinum). I put those plugs in my old tib and drove it for 4 years without a single issue, so I doubt those would be bad as well (although I haven't checked yet).

I'm at a total loss, anyone have any suggestions?

Thanks

 

Bosch likes to flip their wires on the universal sensors. So make sure that is wired right. Kid in my class fried some of his m3's ECU harness because he used one of the Bosch universals and didn't realize the wiring was flipped.

 

I read the Bosch instructions, it was a 4 wire OEM replacement but was labeled universal just because it didn't have the pnp harness for our cars. Same wire colors. I am pretty positive those are wired properly and all good.

Is it possible a TPS could cause all of this?

 

Test the TPS if you suspect it. Be sure the MAFS is facing the right direction. And these cars have a reputation for being hard on/picky about non-OEM O2 sensors (frequent complaints of short useful sensor life) Plugs and wires are pretty cheap, and the Beta seems to do very well with the recommended replacement parts. Even if you replaced good plugs and wires, at least you would have a good set standing by at replacement time . . . they will fail eventually.

If the plugs look really good and the wires do too, and there are no burn/penetration marks on the wires, you might try finding a set of O2 sensors, even if it's just a "oops I didn't need that" return to Autozone the next day, it would tell you something to swap them in.

 

Could well be the TPS. Pull the harness connector off and look at it all really good for wear, dirt, corrosion, or damage.

Wiggle test that too.

I've had some weird shit like this happen when my ECU connector was breaking , and it didn't go away until I replaced it. Had to zip tie it shut to keep the car running normal.

 

if you suspect the TPS, check the TPS voltage from the OBD port while you move the throttle back and forth. Look for a dead spot. it should be fluid increments, no major changes.

The Bosch TPS has two wires which are the same color. Try flipping those.