L
LarryE
Guest
It starts and idles great. When I accelerate it is okay, but at a steady speed it misfires. I can open the throttle wide open and it does great untill I have to lift. I can run the engine up in neutral to about 1750 rpm and it starts to misfire. When the problem started I got a PO320 code and a 1391 . I replaced the crank pos sensor and the cam pos sensor. The 320 code doesn't set now, but it still misfires and the 1391 code ( which is intermitent misfire) does. I checked the vacumn and it pulls 18 at idle and is steady. It drops when I open the throttle, then goes to 25 when I let it shut, then settles at 18. It occurs with various cylinders ( set codes 301,302,304,etc.), so I don't think it is the injectors. There is no test port on the fuel rails so I can't do a pressure test, but the pump and regulator are fairly new. Plugs, wires, cap and rotor are all new. It is pretty consistent about starting to misfire at 1750 rpm with no load, so I am thinking maybe the throttle pos sensor, but it should set a code if it were bad as should the MAP sensor and there are no codes other than the misfire codes.
Thanks
Thanks