MAF causing P0300

[Black8GV6]

I didn't, but I'll need the blocking plates anyways for something down the road.

[Black8GV6]

I took the vac hose off the EGR vavle and plugged in the MAF sensor and the same problem occured, so I just put the hose back on the EGR valve.


This is what my OBDII scanner shows when I have my MAF sensor connected. I'm talking about the FUEL system.

When I put on normal amount of pressure on the gas pedal to drive the below picture happens, fuel says CLOSED and it hesitates and sputters for 10 seconds then it takes off.




When the car finally takes off after it hesitates the fuel says OPEN




When I let off the gas and let the car coast in gear the fuel says OPEN1




And the weird thing is when I let off the gas and let the car coast in gear the fuel says OPEN1 and as soon as I put on the gas the fuel says CLOSED and hesitates and sputters. I am wondering if there is something wrong with my fuel relay since I put gas on and it is like it cuts the fuel off.

When I have the MAF sensor unplugged the car acts normal, I think the fuel stays in OPEN1 and when the car coast in gear then the fuel says CLOSED. It's almost like the car has it backwards when the MAF sensor is plugged in.

[Silvertune]

Did you put the PCV hose on or not? You can't run pulling air in after the MAF. If you are I'm going to come kick your ass. That is BASIC. Did you reset the ECU after unplugging the egr and plugging in the MAF? The MAF calibration resets WITH THE ECU. They have to be powered on and off together.

Get rid of your post MAF leak, unplug the damn EGR, plug in the maf and unplug BOTH your front O2 sensors THEN reset the battery. Closed loop means the ecu is using oxygen sensor feedback. Unplugging the O2's will throw in open loop permanantly so fueling will be determined solely by the MAF. That will let you troubleshoot and see if it's a bad MAF or track down a leak if there is one.

[Black8GV6]

PCV hose connected to intake. I always unplugged the battery before doing anything. I'm going thursday to get hooked up to a smoke machine to see where the vac leak is. I'll unplugged the front two O2 sensors and see how that goes.

[Black8GV6]

Sooooo I found the problem. After all this time is was two O2 sensors were switched, P0300 is gone and car runs like a champ.

[M-Rod]

Time to attempt the manifold swap again?

[Black8GV6]

Yeah, I need to put back on the 6g74 intake mani and install my "silvertuned" 6g74 Throttle body

[Silvertune]

Then go back to the stripppppppppp.

[Black8GV6]

Just to update the thread, turned out that the car didn't like my extended O2 sensor wires, I had new bungs welded closer so I could use the oem sensors and everything is working perfect. Just had to put O2 extenders on both downstream sensors since I have no pre-cats.