01 Mustang issue

JBrown

Member
The car has around 140,000 miles 3.8 & automatic. From day one of us buying the car it's had a vibration. The tires were in bad condition and I thought that was the problem but it wasn't it seems to be when the trans is shifting. At this point it's had new spark plugs & wires, air filter, Trans has been serviced with new filter & fluid. The car broke down about a year ago now and I had to put a new fuel pump in it. The fuel pump was changed a new fuel filter and the gasket for the filler neck and tank plus the tank was cleaned out. After the fuel pump change I noticed the car would surge or have a skipping intermittently going up a hill at times now the skipping or surge is happening more often and not only going up a hill. When I refer to a hill it's a stretch of road with a decent incline. Engine light hasn't come on. The fuel pump came from Advance/ Car Quest auto parts if my memory is working right the fuel pump was a Car Quest brand. Any advice for things to check would be great. This is my daughters car and she said it has got worse in the last week but she waited till today to tell me. And I have to go out of town till Sunday or Monday. My lean too is something with the fuel system. I want to add fuel level don't seem to effect it if it's a 1/4 tank or full tank.
 

6 Shooter

Well-Known Member
The vibration when driving may be related to the U joints. After 140K miles, there is a possibility of getting some trash in the fuel line that has ended up in the fuel injector screens. Especially if you "cleaned out the tank". The fuel injectors can be sent to a guy in Florida (Injector Man) who cleans the screens, replaces the O-rings, adjusts the flow pattern, and bench flow for balance of all 6 injectors for $120.
 

fasterthanyou

Active Member
Is the vibration vehicle speed dependent or engine rpm dependent?
Or neither? Is it only when it shifts between gears?
If its the latter, and the trans filter/fluid is new. Try adding 4 oz of ford friction modifier to the transmission.
Aode/4r70w transmissions can be finicky when they get a lot of mileage on them especially in hills/mountains. They get hot and the fluid breaks down making the shifts chatter.
 

JBrown

Member
Is the vibration vehicle speed dependent or engine rpm dependent?
Or neither? Is it only when it shifts between gears?
If its the latter, and the trans filter/fluid is new. Try adding 4 oz of ford friction modifier to the transmission.
Aode/4r70w transmissions can be finicky when they get a lot of mileage on them especially in hills/mountains. They get hot and the fluid breaks down making the shifts chatter.
For now I have a few things going on with the car. Before the engine started running rough the car would have the vibration once it shifted out of 2nd and into 3rd. I did add a modifier but it was a Lucas brand product that was to improve shifting. How the engine is running now matches up with the problems you would have from a bad O2 sensors but I thought if the O2 sensor was bad or going bad the check engine light would come on. Thank you. I only get to drive the car when my daughter thinks there is something wrong or she knows something is wrong. The rough running she thinks started about a week before my post and it continued to get worse. I found out the day I posted for help. She lives at home and it took a week for her to say something!!!
 
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