Howdy forum, I've been tracking various stock engine problems ( 89 V6 2.8 ) mostly idle related ( Rough idles, searching, idle hang )and have been through most of the components making some progress. Just replaced a faulty egr and maf sensor which cleared up a few more issues but after one successful test drive the engine now experiences bogging during acceleration. I don't get any codes just a loss of umph. No matter how much throttle I give it. I disconnected the maf again and performance seems to improve ( no bogging ) By disconnecting the maf ( which throws a code but runs better ) Am I in open limp home loop mode? Or are all the other sensors such as the tps still being used by the ecm? If the car is in closed loop but operating better with a disconnected maf than I would suspect the new maf or maf relay is the problem. All the standard components check out to specs. ( current maf is a dura last ) Thanks!

 

This doesn't answer your specific questions, but have you checked your fuel pressure? I have the came car (year/engine/tranny), and I was pulling my hair out last year over similar issues (bogging on acceleration, etc) for weeks, with no improvement after replacing the MAF among other things. I finally checked my fuel pressure, and found it was at 20% of where it should have been. I replaced the fuel pump and it ran like a champ. I was in no mood to drop the rear axle and fuel tank to get to the pump, so I pulled back the carpet over the shelf behind the rear seat, cut an access hatch and changed the pump out in 30 minutes. (I sprayed a fine water mist across the area while I was cutting, and had a fire extinguisher handy, but the cutting procedure was thankfully uneventful.)

Just a thought. Hope you're making headway...I have a love/hate relationship with my '89...