Just bought an Subaru Leone EA82T '87. Fires right up no problem and drives great. But 10min into the drive I start noticing a slight hesitation on throttle, like a plug wire problem would feel like. Then the car starts to lose power and starts to sputter and bog and backfire until it doesn't have the power to drive on and stalls. Then I have to wait up to an half an hour to be able to get it running again. Any thoughts on this?

Two things come to mind. Could be a failing fuel pump or a leaking fuel pressure regulator. To check the FPR, just pull the vacuum line. If the line has fuel, then the regulator is leaking. 

Sounds like a clogged catalytic converter, or exhaust pipe problem to me, especially if its not lighting the engine light

Probably fuel pump or clogging in tank filter sock.

Check the pressure.

Another possibility would be the fuel tank not venting properly.

 

Try driving around with the gas cap loose or off, see what that does.

have you diagnosed ECU codes?

Something like coolant temperature sensor could do this also.

I love how quick you guys are to reply to problems on this forum

 

I'm going to dig in and try to fix this problem this weekend. I haven't noticed any check engine light so far.

 

The to-do list:

 

(The easy stuff first)

- Check for ECU codes

- Air filter

- Check sparkplugs and wires

- Compression test

- Fuel pressure test

- Check for vacuum leaks

- Coil

- Checking all grounds

- Unplug and clean all connectors

- Fuel filter

- Injection cleaner

- Drive with the gas cap off

- Check for leaking fuel pressure regulator

- Check for exhaust leaks

 

 

- New temp sensor

- Clean/change the MAF

- Change the fuel pump and check the sock

- Crank sensor

You may know this, but I'll add it for anyone new who may not realize it. The coolant temp sensor is separate from the sensor for the temperature gauge. The CTS is the one that can effect engine running, and it can fail without causing the ECU to show a code.

You may know this, but I'll add it for anyone new who may not realize it. The coolant temp sensor is separate from the sensor for the temperature gauge. The CTS is the one that can effect engine running, and it can fail without causing the ECU to show a code.

I knew they were a seperate thing in the USDM cars. I have a JDM car so I don't have the temp gauge Thanks for the heads up

I knew they were a seperate thing in the USDM cars. I have a JDM car so I don't have the temp gauge Thanks for the heads up

 

Got any pics of the instrument cluster ? I've never seen any without the temp gauge It's usually tacho, oil pressure or volt meter that is missing in these if it's analog cluster. Oh are you sure it's JDM and not European model and do you have right hand drive in it ?

Edited December 23, 201510 yr by -tombba-

Backfire means that you temporarily lost spark.  When I had a bad coil, just before it went out all together, it acted exactly as you described.  Coils are cheap and a new one really adds power.

My Guess would be a cloged fuel filter Or a bad ground to the body

Sounds like a clogged catalytic converter, or exhaust pipe problem to me, especially if its not lighting the engine light

I agree with this assessment.. I've seen this in multiple models: 1999 Chrysler Town and Country, 1995 Ford Windstar.  remediate a "plugged cat".