I have a 1995 Ford Aerostar 4wd 4.0L and it has been giving me problems almost the whole time I have owned it. I have replaced the MAF and O2 sensors three times now. I replace the sensors and it runs better but in a week of two the CE light comes back on and almost always reads the same codes: 185,186,187 which is MAF lower than expected, Injector pulse width High, and injector pulse width low. Can anyone help shed some light on my problem The O2 is brand new and I just replaced the MAF with a known good one from my buddies '90 Aerostar. It didn't throw a code for a week and then the CE light came on earlier this week. FYI Van has 188,000 miles. Symtoms that it has are Loss of power especially up top, it misses like crazy under part throttle load but at WOT it doesn't really miss at all it just lacks power and every once in awhile it will ping.

 

possiblities
1. leaking intake plenum/intake manifold...bolts loosen from Ford V6 vibration and gaskets suck or blow out...test with spray can of throttle body, carb or other intake cleaner...spray in one area time...miss lessens or goes away=leak found.....
tighten all intake manifold/plenum bolts....if problem still exists, replace gaskets....

2. injectors, intake valves and combsution chamber with carbon/fuel byproducts buildup....search Aero forum for Seafoam soak and water injection cleaning

3. Leak in air tube between MAF and throttle body
4. Corroded intermittent contacts on ECU/PCM connectors
Top LH side of safety wall, on powertrain control module (PCM) (A8)
clean with spray contact cleaner and then protect with silicone spray before reconnecting

5. Intermittent poor grounds to ECU/PCM
G103 Blk/Lt Grn Top LH center of safety wall, near windshield wiper motor (A8)

G203 Pink/Org Behind center of I/P, below RH side of radio (B10)

 

Cool thanks for the tips. It seems like it really doesn't miss all that much at idle ussually unless it's really hot outside. One thing I forgot to add which is probably major is the miss gets 100x's worse when it is damp outside it actually will sound like it's back fireing through the intake Light popping noises under the hood. then when I drive it for a little while it cleans up alot but still has the problems I listed above. I kind of think that the misfire/backfire during damp conditions is a seperate issue though but I could be wrong. I am def. not a mechanic.

 

engine miss during damp weather is usually spark plug wires old and insulation broken down....Aero plug wires last abt 5-10 years depending on climate, temps and engine load
the EDIS extra high voltage system on Aeros is extremely hard on plug wires
replace only with Motorcraft or Autolite brand....they designed the special coil pack connectors....group members have longest replacement life and least problems from these 2 brands.....
expensive but last....don't want to replace every couple years....you will see what we mean after your first experience
use lots of ignition silicone dielectric grease in spark plug boots and coil pack connectors....seals out moisture and makes them far easier to get off next time

once we get the miss/knock/ping cleared up, you are going to love that Aero....a fine freeway cruiser, low maintenance
and NO gold plated import parts prices

 

Cool, I do have new plugs and new motorcraft wires sitting in it and waiting for me to replace them. I have done it once before and it took forever a couple of the plugs are a huge pain to get to. I did replace the wires before but they aren't motorcraft wires I have no idea what brand they are but they were fairly cheap. If the weather is nice this weekend I am going to try to run a can of seafoam through a vacume line and then replace the plugs and wires. I use my van for a work van, as I repair furniture for a living and need the space for hauling my tools and parts that I need. The 4wd is also awesome in the winter, I had no problems getting around last winter when we had a snow storm that dropped 6-8" of snow by midmorning. I bought it 2 years ago and have had nothing but problems with it. If I could ever get it to run right my life would be so much easier as I spend 4-5 hours a day in it. I have put over 80,000 miles on it in the last two years. This hot weather we're having isn't helping things either. I actually drove my DD '05 S'crew instead of the van on a couple of the hottest days because when the temp is around 100 degrees it runs incredibly bad. I really appreciate your help.

 

MAF is different between '90 and '95 Aero 4L.....
also run a bottle of injector cleaner thru gas tank, Gumout Regane or Chevron Techron Concentrate are the most effective...the injectors plug and gum up internally around pintle and in nozzle where Seafoam won't reach.....

here's more info to use troubleshooting analysis
http://fordfuelinjection.com/

 

I just compared part#'s at Rockauto and they list the same part# for the '90 and the '95. The plug is the same and from my experience with my '99 mustang and the MAF system that mustangs use, a Ford MAF is a Ford MAF as long as the plug is the same the calibration for the MAF is in the PCM.

 

Hi Velocity:

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It looks like you are in good hands with 96_4wdr