youre getting a code for the 3-4 shift solenoid. code 85. Ford OBD Trouble Codes – that is most likely your issue, but it wouldnt hurt to check a couple other things first.
like crak said, check the vac lines, especially the one for the modulator. also, pull the hose out of the modulator, if theres any fluid in the hose then the modulator is going bad and needs replaced. its cheap, like $20 at napa. bad modulator can screw up your shifts in the trans.
also check the vac lines for the egr, and check the egr itself. egr helps feed vacuum to the trans for shifting, so bad egr can starve the trans for air and slowly kill it, and can screw up your shifts if it is bad enough.
one more thing, if you havent changed the trans filter ever, it would be a good time to change it. clogged filter can mess up your shifts too. changing filter is easy, just drain fluid, drop pan, filter is right there. if you have good fluid then its ok to resuse it, but if it is iffy then just put new fluid in there. you will probably only get 4-5 quarts to come out since most of the fluid stays in the converter.
like crak said, check the vac lines, especially the one for the modulator. also, pull the hose out of the modulator, if theres any fluid in the hose then the modulator is going bad and needs replaced. its cheap, like $20 at napa. bad modulator can screw up your shifts in the trans.
also check the vac lines for the egr, and check the egr itself. egr helps feed vacuum to the trans for shifting, so bad egr can starve the trans for air and slowly kill it, and can screw up your shifts if it is bad enough.
one more thing, if you havent changed the trans filter ever, it would be a good time to change it. clogged filter can mess up your shifts too. changing filter is easy, just drain fluid, drop pan, filter is right there. if you have good fluid then its ok to resuse it, but if it is iffy then just put new fluid in there. you will probably only get 4-5 quarts to come out since most of the fluid stays in the converter.
