Miss and Weak After Warm Up.
#1
01-26-2013, 05:44 PM
Miss and Weak After Warm Up.
I have a 97 F350 auto I have owned since June. When I bought the truck it felt it lacked in the power department but figured it would be a simple fix. It has been quite the opposite. I have cleaned and/or swapped most sensors that can cause a problem. CPS, VSS, ICP, ECM, and IDM have all been changed out with my 96 powerstroke auto that runs great. I have also replaced the transmission and torque converter since I was getting a p1728 code. Recently I changed to the IPR O rings with no change. Fuel filter and oil are very fresh. FPR screen is clean and at schrader valve I get 50-70 lbs. of pressure. I am able to maintain 17 to 20 lbs of boost according to my gauge teed into the map line.
The truck has never set a "check engine" light, does not smoke, nor do I have any blow by via the oil fill. The truck starts easily at any temp. hot or cold and has never died on me. When cooler weather hit low 40s the truck finally ran like it should. It will run this way for 5-10 minutes and it slowly loses power and then develops a miss or lug when cruising, especially after an up shift. The truck will pick up a bit after 2900 RPM. It does maintain highway speed of 65 to 70 just fine, but it does have to downshift on hills. Also, the shift from 1st to 2nd is very very firm and shifts smooth when cold. Today I had a contribution test and injector buzz test that passed. I was hoping the HPOP would be out of norm but at WOT from 50 -80 mph it held a constant 2400 @ICP with 31% duty cycle. I have inspected my fuel filter and it is not black with oil so I don't think the injectors are leaking. The EBPV seems to work fine. When it its cold out and the engine is cold I can hear it opening and closing up until it warms up.
Sorry, if this is long winded. I am just trying to explain everything I have tried. I am about to give up on the truck as I can not just keep throwing money at it. Thanks for your time and any input.
PS I also thought about trash in the tanks, but the truck will run bad as well if I leave it plugged in over night to maintain heat.
The truck has never set a "check engine" light, does not smoke, nor do I have any blow by via the oil fill. The truck starts easily at any temp. hot or cold and has never died on me. When cooler weather hit low 40s the truck finally ran like it should. It will run this way for 5-10 minutes and it slowly loses power and then develops a miss or lug when cruising, especially after an up shift. The truck will pick up a bit after 2900 RPM. It does maintain highway speed of 65 to 70 just fine, but it does have to downshift on hills. Also, the shift from 1st to 2nd is very very firm and shifts smooth when cold. Today I had a contribution test and injector buzz test that passed. I was hoping the HPOP would be out of norm but at WOT from 50 -80 mph it held a constant 2400 @ICP with 31% duty cycle. I have inspected my fuel filter and it is not black with oil so I don't think the injectors are leaking. The EBPV seems to work fine. When it its cold out and the engine is cold I can hear it opening and closing up until it warms up.
Sorry, if this is long winded. I am just trying to explain everything I have tried. I am about to give up on the truck as I can not just keep throwing money at it. Thanks for your time and any input.
PS I also thought about trash in the tanks, but the truck will run bad as well if I leave it plugged in over night to maintain heat.
