Questions and Answers

Ford Aerostar Has A Bad Vibration Q. Hoping you can help me out! I have a 1996 Ford Aerostar AWD. 160,000 kilometers on a 4.0 liter fuel injected engine, automatic transmission P/S, A/C, cruise control and ABS brakes. Plugs (platinum) and wire set were replaced at 120,000kilometers. At 157,000 kilometers I added a fuel injector cleaner to a tank of fuel.

Several months ago, August 2003, while returning from vacation at approximately four hours driving time at 110 kph, the van vibrated badly under acceleration only and ran like this for several kilometers. Thinking I picked up some bad fuel or water from my last fill up I gave the engine full throttle and after a minute or so of rough driving the engine miss cleared and ran fine for several months. (I changed my fuel filter at the end of the trip).

I have experienced the same symptoms two or three times since and it only occurs at highway speeds. I changed the fuel filter again and checked it for water or dirt and was clean.

I also changed the air filter element, PVC Valve, and have noticed now that the vehicle, at any steady speed appears to surge (speeds up and slows down constantly causing a very rough ride and increased fuel consumption).

I also changed all he shocks with Monroe Sensa-Trac and thought the rough ride was due to the new shocks but have since ruled that out. I have also noticed that the odometer also rapidly fluctuates at highway speeds.

I was told by a mechanic that my fuel pump could be on its way out or my speed sensor may be faulty, but after visiting your web site and reviewing some similar problems encountered by owners different vehicles I am wondering if it could be my O2 or MAF sensor.

This may not have any thing to do with my problem but during extremely hot weather, 28° to 30° C I noticed a loud humming vibration coming from the air intake just past the air cleaner housing only at idle.

Thanks for your input!!
Mike

A. Whenever I get a drivability problem like this on a Ford product, I always check the Mass Airflow Sensor (MAF) first. They are prone to getting dirty and causing all kinds of drivability problem.

I think if you give it a good cleaning the problem will disappear. Here's a good tip on how to fix it. Ford Expedition P0171 & P0174 and Ford Mass Air Flow Sensors.