1997 Aerostar AWD / Runs rough / check engine light stays on

Tiny
SJSANDJMS
  • MEMBER
  • 1997 ALL OTHER MAKES ALL OTHER MODELS
Hi, We have a 1997 Aerostar AWD, 4.0, Miles 122,000. Where do I begin! Van's check engine light has been on. We have taken this van to have the codes read. After replacing the spark plugs, wires, air fliter. Codes said replace Coil, Mass Airflow Senser, and one more part I can't remember right now. (My husband does all the work on it) All that was done. Anyhow, engine seems to begin to run better, but then starts running rough and by the way the Mass airflow senser vibrates so loud, it's embarrassing! A really loud humming noise. This happens when it gets warm or sittiing in a drive thru on hot or warm days. Usually never a problem when cold. The old one did the same thing, most of the time only in the idling state. We thought replacing this would stop this problem but it has not. Back to the engine, the roughest running is at the idle. Sometimes it even shuts off. It always starts. Running low speeds and idle engine light blinks running higher speeds goes back to steady on. It was put back on the computer, they can not tell us what the problem is, all they can say is for some reason it is missfiring on the #2 and #4 cylinders. All wires have been checked and rechecked. All wires and plugs are brand new. Once in a while it seems to run better, but most of the time not. What else can we check? Help! We've put money and more money in the van with no real results yet. Thank-you!
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Wednesday, March 28th, 2007 AT 6:55 AM

7 Replies

Tiny
KIN CHAN
  • MEMBER
Come on!. Its an early OBD2 sys. No big deal.
NOW!
Whos they?
Whats the code?
Why aint u fix the chk eng lite when it lit up for years?
What make u think u can fix the car when average auto shp are struggling with no success by throwing parts at these 90's and newer cars which they deal with it days in and days out?
Too good to be true is too good to be true --> cheap = nuthing !
I'll try to diagnose what problematic area over the net here. But 97' chevy aint ur 73' chevy pu'. We can pin point the area and most likely u have to send it to a real shop to fix it and verify the repair. Good enuff. Answer me some questions
whats the codes? --> Give me the code!
How and when did the chk engine lite came on?
These are direct questions ->give me direct answer with no opinions. Msg me when u have some answers and we'll go from there. Good luck man
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Wednesday, March 28th, 2007 AT 7:31 AM
Tiny
SJSANDJMS
  • MEMBER
OK, I am not savy with a lot of computer language used, what is OBD2?
"they" is an auto mechanic shop, Goodyear, Baggs Tire and Auto.
The Check Engine light came on when a purdge valve sencer needed to be replaced. I tried to describe everything we have done so far. And to describe how the van still runs. I do not know the codes. Only what I was told by the mechanic. They van has ran perfectly fine up till the past month or so. The light did not begin coming on and the blinking again until recently in the time I have spoken of.
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Wednesday, March 28th, 2007 AT 8:03 AM
Tiny
KIN CHAN
  • MEMBER
|OBD2 = on board diagnostic 2. For full detail. Look up on this website.
Go to auto zone and pull the codes 1 more time.
The most closet analogy on chk engine lite is. Let me think
imagine the computer management system consit of a lot of sensor devices both mechanical and electronics. Well so are our human body with organs and soul. Well if ur stomach hurt, ur toe, ur heart ur head ur. Etc.U scream. Or maybe winning the lottery.U scream too. Well the chk engine lite is the same thing. Any of these items within the management system have problems -> the chk engine lite will come on. So. Whatever it happen last time. It maybe or may not be the same thing. Until u get the codes or if u pay a shop. They should be liable to have in on ur work order or reciepts. Just that simple. So how bout some codes?
Msg me when u get some answer. Heeee hawwww
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Wednesday, March 28th, 2007 AT 4:05 PM
Tiny
SJSANDJMS
  • MEMBER
OK
I got some codes Also want to mention this once more this is a Ford Aerostar AWD 4.0
Codes found 3
Code 1 - DTC P0302 Cylinder 2 Misfire Detected
Code 2 - DTC P0304 Cylinder 4 Misfire Detected
Code 3 - DTC P0171 System Too Lean (Bank 1)
Now I know this is calling for a Upstream Sensor but will this cause the other problems? The misfire? Thanks
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Wednesday, March 28th, 2007 AT 4:29 PM
Tiny
KIN CHAN
  • MEMBER
Both are system and misfire codes not sensor codes. So unfortunately u can't just replace a sensor to fix ur problem without understanding how the system work. Whatever cause 1 bank to run lean it probably cause the misfiring. What had been done to the car prior to the symptoms.
How many miles?
Fuel injectors service?
Did the shop chk the fuel trims or O2 activity?
Does this problem happen all the time or it just warm?
Was it worse at idle / low speed or any speed range?
---> keep answering and we'll nail down to the area pretty soon.
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Wednesday, March 28th, 2007 AT 5:32 PM
Tiny
SJSANDJMS
  • MEMBER
Miles - 123,000
No fuel injectors have been serviced
I was not at the shop with my husband, he says they did not chk either fuel trims or O2. Just codes mainly. And cleared them, to recheck them again.
This problem seems to happen all the time, but most noticeable at idle or low speeds. Once in a while will idle better than other times.
As for what has been done to the van so far once it began to run badly
1st we changed plugs and wires and air filter.
After that van still ran roughly but seemed a little better. Code light was still on so we had the codes read.
2nd changed coil, Mass Airflow Sensor, and EGR Pressure sensor. Seemed to run a bit better again, but still has the misfire.
One note: while changing the plugs he accidentally broke one vacuum line that had to do with the air conditioner. It made all the air just come out the defrost. But he also fixed this and the air works fine.
One more thing the Mass Air Flow Sensor or maybe the box will hum or vibrate very loudly once it gets warm or hot. The old one did the same thing. The new one does it as well. What could be causing that?
Thank-you
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Wednesday, March 28th, 2007 AT 10:12 PM
Tiny
KIN CHAN
  • MEMBER
I might get kick outta here for saying the following :
but then again.I love my mom. She taught me to tell the truth. So make sure u can handle the truth!
An internal intake/vacuum leak might cause these symptoms. If this car came to my shop.I'll chk the fuel trims and O2 with scanner or may be flow propane to chk the condition. Okay. Now this is the last thing u can do to identify the problem. And I mean identify not fixing. Find a major vacuum inlet port. Flow propane to it while it is acting up. If condition improve at idle. Then u can conclude it is a high possibility of intake manifold vac leak. Since u have no smoke machine.U can't do a vac leak chk. Come on man! Wake up. If I work at burger king handing out burger.I could have learn how to plug a code reader into a car and look up the codes in 5 minutes and start working at local parts store. To intrepret the live datas on a scanner and draw conclusion to indentfy problems is a MECHANIC. We've got guys here all day long hanging parts for under $10 an hr. Thats easy stuff. Pharmacy give u the medicine to cure ur sickness. Now what to take is ur doctor. Got it. This car need an L1 certify mechanic to fix.
L1 = engine performance & emission repair. Itis impossible to make some1 overnite with no training, experiences and equipment to just fix its own high tech problem. Good luck and keep me update

HEEEEEE HAWWWWWWW!
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Thursday, March 29th, 2007 AT 7:15 AM

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