I thought I would post my findings here. I have had a strange misfire on my Sport LS since I have had it. I wasn't sure if it was even a misfire. It shook upon startup but didn't feel bad or harshly buck upon acceleration like the usual coil problem most of us have faced. I had people tell me it was possible I had a sticking valve/bad guide. I guess a certain batch of 3.9s had this issue. You really wouldn't notice it when the car was warm. I thought maybe it was an injector and the computer did tell me I had a cylinder #3 misfire. I replaced that coil twice and finally decided to swap two injectors around to see if the error moved. The check engine light never came back on, so I ignored the problem.
Well, I got a bug up my butt and said, wth...I ordered an injector for $6x.00 from Rock Auto and it came yesterday in a Ford Motorcraft box. I swapped out the injector this morning and it seems to have fixed the problem! No shaking on startup and the car has more power. Not only that, my mileage started increasing today as I drove it. I am shocked. I am glad I went at it with the shotgun approach.
I never had a problem with it starting hot, so I don't think the injector was leaking, but hard to say.
I found that you can check for leaking injectors by lifting the rail to get the injectors out of their bores, as they will stay in the rail with the help of the clips. Of course, when lifting the rail or moving the injectors in any way, be sure your fuel pressure is 0. Build the pressure after you have the injectors out of the bores. I didn't see any leaks. Bleed the pressure before lowering the rail to install the injectors in their bores.
It took me over an hour to get the injectors out the first time, but about 15 minutes the second. When I swapped the injectors, I made sure to move the one I thought was bad to the end of the rail for easy access.
ANYWAY...I think it is time to start modding now.
Well, I got a bug up my butt and said, wth...I ordered an injector for $6x.00 from Rock Auto and it came yesterday in a Ford Motorcraft box. I swapped out the injector this morning and it seems to have fixed the problem! No shaking on startup and the car has more power. Not only that, my mileage started increasing today as I drove it. I am shocked. I am glad I went at it with the shotgun approach.
I never had a problem with it starting hot, so I don't think the injector was leaking, but hard to say. I found that you can check for leaking injectors by lifting the rail to get the injectors out of their bores, as they will stay in the rail with the help of the clips. Of course, when lifting the rail or moving the injectors in any way, be sure your fuel pressure is 0. Build the pressure after you have the injectors out of the bores. I didn't see any leaks. Bleed the pressure before lowering the rail to install the injectors in their bores.
It took me over an hour to get the injectors out the first time, but about 15 minutes the second.
When I swapped the injectors, I made sure to move the one I thought was bad to the end of the rail for easy access. ANYWAY...I think it is time to start modding now.
