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1998 Forester
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8 Posts
Discussion Starter #1
My mechanic has always been awesom about finding things in the past - but he is stumped on this one. He is posting to Japanese forums, and asked me to ask around on English ones to look for a solution to a strange problem......

My 98 non-turbo forester with 150K started acting weird in late November. Cold or warm, the car would sometimes run fine, but every now and then act like it was totally out of gas - rpm's would drop to 1000, surge up, drop to 500, surge up, then the car would die. I can restart it, but the same thing happens again within thirty seconds or so. This didn't happen on every trip - but once it started, it would last for 5-10 minutes - wether or not I drive it. Sometimes It would lurch and gasp into the driveway, but An hour later I could start it up and drive it with no problem for a day or two.

I took it to a mechanic with no waiting list who couldn't find anything wrong, but he changed the fuel filter in case there was something bad there. He said it was very dirty, but changing it didn't fix things. First trip was fine - second "trip" it died in the driveway. He told me to put injector cleaner in, which I did, along with a new tank of Shell. No dice, so I got on the waiting list for my preferred mechanic.

I took the car to him last week. He couldn't reproduce the problem. He drove it to and from the shop every day - 200 miles, a new tank of gas from a Union 76 station - couldn't reproduce the problem. Both mechanics say they are getting no codes from the computer.

Monday, I had mechanic #2 replace the front 02 sensor, which he said was a little out of range, and Tuesday I went in to pick up the car. He never saw the symptoms - until I sat down in it and tried to start it. It went crazy on me again - dying in the shop bay. Mechanic ran over, threw open the hood and started poking, sniffing and listening to everything he could think of to poke, sniff or listen to. He tried revving the engine very high, he tried puling off various tubes, he tried manually forcing the (ezr?) Nothing worked except that over the course of fifteen minutes or so, the problem gradually went away. He took it on a test drive, and the computer reported no problems. I had to pick up my daughter, so I took it on a twenty minute drive, and returned the car to him with nothing abnormal to report.

Overnight, he hooked up to a fuel pressure guage - normal. He says the exhaust smells a little bit lean, but not terribly. He says that there is a problem with WRX that is similar, but it doesn't go away when it is happening. He said I should search english language forums for "big misfire" - I am starting here.


Has anything like this happened to anyone else? Any ideas of what to check?


Thanks for any tips you can give.

-Adam
 

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2007 Mitsubishi Pajero 5spd Automatic
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3,594 Posts
You did not say if you got the spark plugs checked and wires. Also the coil should be checked. When was this changed?
It can even be the fuel pump.
In the end I'm not a mechanical genious so hopefully someone else will drop in something useful.
Good luck
 

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1998 Forester
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8 Posts
Discussion Starter #3
He checked the plugs and plug wires. He replaced the coil, because like the O2 sensor, it was "nearly out of range."
 

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05 FXT 5MT
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255 Posts
I vaguely remember a similar symptom being related to the fuel pickup sock coming off the pump and randomly obstructing the opening.

Might be worth a look......
 

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Registered
1998 Forester
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8 Posts
Discussion Starter #5
Good tip

I vaguely remember a similar symptom being related to the fuel pickup sock coming off the pump and randomly obstructing the opening.

Might be worth a look......
The word "random" is very encouraging, because that is what it feels like - no pattern I can find anywhere.

I'll ask the mechanic to look at it. Do you remember if it was something you were able to conclusively identify once you found it? I am not familiar with that part of the pump - was it clearly not affixed properly?

Thanks
 

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16 Posts
Try cleaning the throttle body and the iac valve. Carbon can gum things quite badly.
Scan the range for the TPS sensor.
Check the fuel pressure and observe varying fuel pressure (faulty regulator) or too low/too high fuel pressure (bad fuel pump).
Check for corrosion at the fuse box terminals.
Make sure alternator connector is good and secure.
Check electrical harness connectors for corrosion.

Maybe these tips will help. Good luck, and do let us know the outcome of your repair so that future members can refer to this situation.
 
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