Subaru Liberty 1994/Petrol. Vehicle starts ok then surges and loses power. Starts again fine but continues same pattern. I can drive 50km one day and it only surges once, then next day it starts and stops continually. Very frustrating. I have replaced fuel filter, but no improvement. Temperature never changes. It's done over 200,000 km, Any ideas?

is this AFRICA KB240 , 2.4L petrol.?????????
we have no KB here in USA not a one. no parts, no books on it. (heck no WIKI on KB. ouch)
so it starts and drives ok/
but idle surges (up/down RPM) means PCM can not control IDLE RPM at all, and has many causes.
you can drive it fast and even up hills or at WOT.?

but only stopping at say a stop sign the engine surges.
well lets work that 1 problem if is just 1.
EGR struck open, is common. (if has one)
IAC stuck the idle air controls valve is stuck and needs cleaning, of gunk off it
thermostat not bad, 180F (82c) is good but 150 is bad. hot normal engine.
VVT failing . if has VVT. (cam timing variable)
VVT engine most times have no EGR valve.
spark wires bad, seen on new cars with no COPS.
seen with COIL packs and 4 HV logs and 4 HV wires
and HV wires bad, or just one.
as I said no books here on KB at all. zero.
as in service manuals.

More than likely it is a FUEL PUMP that is failing or a Clogged Fuel Filter.

When the pressure is releived, the sediment will settle and allow you to start again but then get blocked again and repeats,,

It could many things, please go for a scanner test

Its a hot start issue.

Can be related to low fuel pressure or problem with crank sensor.

Also it can be weak battery or starter.

But possibilities are to be inspected to confirm what exactly it is.------

To troubleshoot and confirm the issue,i suggest you refer few solved help links with similar types of problem like yours:------

Click the link below:------

1991 Toyota Trecel: Engine Starts fine but dies when gets Warm?

http://whatisbyme.blogspot.in/2012/05/1991-toyota-trecel-engine-starts-fine.html

-------------

1994 Toyota Pickup: Starts fine but dies in few seconds?

http://howtobyme.blogspot.in/2012/05/1994-toyota-pickup-starts-fine-but-dies.html

------------

1995 Lexus LS400: Running Hot?

http://whatisbyme.blogspot.in/2012/05/1995-lexus-ls400-running-hot.html

------------

2002 Toyota Camry: Puff of Blue or White Smoke while Starting?

http://whatisbyme.blogspot.in/2012/05/2002-toyota-camry-puff-of-blue-or-white.html

------------

Multiple problems on car: Car runs hot, A/C blows hot and car starts surging?

http://schematicsdiagram.blogspot.in/2012/04/multiple-problems-on-car-car-runs-hotac.html

--------------

Delay starting on Toyota Prius?

http://schematicsdiagram.blogspot.in/2012/02/delay-starting-on-toyota-prius.html

-----------

Honda car will not start intermittently?

http://technoanswers.blogspot.in/2012/02/honda-car-will-not-start-intermittently.html

--------------

Vehicle Starts, Runs and Loses Power

http://whoisbyme.blogspot.in/2012/07/vehicle-startsruns-and-loses-power.html

--------------

Intermittent starting issues on Volvo 760?

http://schematicsdiagram.blogspot.in/2012/02/intermittent-starting-issues-on-volvo.html

-----------

Car starts and cuts off immediately?

http://repairhelpcenter.blogspot.com/2012/01/car-starts-and-cuts-off-immediately.html

-----------

Car won't start when cold?

http://schematicsdiagram.blogspot.com/2011/12/car-wont-start-when-cold.html

===========

These details will help.

Thanks.

Vehicle Starts, Runs and Loses Power

http://whoisbyme.blogspot.in/2012/07/vehicle-startsruns-and-loses-power.html

--------------

Its a hot start issue.

Can be related to low fuel pressure or problem with crank sensor.

Also it can be weak battery or starter.

But possibilities are to be inspected to confirm what exactly it is.------

To troubleshoot and confirm the issue,i suggest you refer few solved help links with similar types of problem like yours:------

Click the link below:------

1991 Toyota Trecel: Engine Starts fine but dies when gets Warm?

http://whatisbyme.blogspot.in/2012/05/1991-toyota-trecel-engine-starts-fine.html

-------------

1994 Toyota Pickup: Starts fine but dies in few seconds?

http://howtobyme.blogspot.in/2012/05/1994-toyota-pickup-starts-fine-but-dies.html

------------

1995 Lexus LS400: Running Hot?

http://whatisbyme.blogspot.in/2012/05/1995-lexus-ls400-running-hot.html

------------

2002 Toyota Camry: Puff of Blue or White Smoke while Starting?

http://whatisbyme.blogspot.in/2012/05/2002-toyota-camry-puff-of-blue-or-white.html

------------

Multiple problems on car: Car runs hot, A/C blows hot and car starts surging?

http://schematicsdiagram.blogspot.in/2012/04/multiple-problems-on-car-car-runs-hotac.html

--------------

Delay starting on Toyota Prius?

http://schematicsdiagram.blogspot.in/2012/02/delay-starting-on-toyota-prius.html

-----------

Honda car will not start intermittently?

http://technoanswers.blogspot.in/2012/02/honda-car-will-not-start-intermittently.html

--------------

Vehicle Starts, Runs and Loses Power

http://whoisbyme.blogspot.in/2012/07/vehicle-startsruns-and-loses-power.html

--------------

Intermittent starting issues on Volvo 760?

http://schematicsdiagram.blogspot.in/2012/02/intermittent-starting-issues-on-volvo.html

-----------

Car starts and cuts off immediately?

http://repairhelpcenter.blogspot.com/2012/01/car-starts-and-cuts-off-immediately.html

-----------

===========

These details will help.

Thanks.

HOT/WARM START ISSUE

Its a hot start issue.

Can be related to low fuel pressure or problem with crank sensor.

Also it can be weak battery or starter.

But possibilities are to be inspected to confirm what exactly it is.------

To troubleshoot and confirm the issue,i suggest you refer few solved help links with similar types of problem like yours:------

Click the link below:------

1991 Toyota Trecel: Engine Starts fine but dies when gets Warm?

http://whatisbyme.blogspot.in/2012/05/1991-toyota-trecel-engine-starts-fine.html

-------------

1994 Toyota Pickup: Starts fine but dies in few seconds?

http://howtobyme.blogspot.in/2012/05/1994-toyota-pickup-starts-fine-but-dies.html

------------

1995 Lexus LS400: Running Hot?

http://whatisbyme.blogspot.in/2012/05/1995-lexus-ls400-running-hot.html

------------

2002 Toyota Camry: Puff of Blue or White Smoke while Starting?

http://whatisbyme.blogspot.in/2012/05/2002-toyota-camry-puff-of-blue-or-white.html

------------

Multiple problems on car: Car runs hot, A/C blows hot and car starts surging?

http://schematicsdiagram.blogspot.in/2012/04/multiple-problems-on-car-car-runs-hotac.html

--------------

Delay starting on Toyota Prius?

http://schematicsdiagram.blogspot.in/2012/02/delay-starting-on-toyota-prius.html

-----------

Honda car will not start intermittently?

http://technoanswers.blogspot.in/2012/02/honda-car-will-not-start-intermittently.html

--------------

Vehicle Starts, Runs and Loses Power

http://whoisbyme.blogspot.in/2012/07/vehicle-startsruns-and-loses-power.html

--------------

Intermittent starting issues on Volvo 760?

http://schematicsdiagram.blogspot.in/2012/02/intermittent-starting-issues-on-volvo.html

-----------

Car starts and cuts off immediately?

http://repairhelpcenter.blogspot.com/2012/01/car-starts-and-cuts-off-immediately.html

-----------

Car won't start when cold?

http://schematicsdiagram.blogspot.com/2011/12/car-wont-start-when-cold.html

===========

These details will help.

Thanks.

Its a hot start issue.
Can be related to low fuel pressure or problem with crank sensor.

Also it can be weak battery or starter.

But possibilities are to be inspected to confirm what exactly it is.------

To troubleshoot and confirm the issue,i suggest you refer few solved help links with similar types of problem like yours:------

Click the link below:------

1991 Toyota Trecel: Engine Starts fine but dies when gets Warm? http://whatisbyme.blogspot.in/2012/05/1991-toyota-trecel-engine-starts-fine.html

-------------
1994 Toyota Pickup: Starts fine but dies in few seconds?

http://howtobyme.blogspot.in/2012/05/1994-toyota-pickup-starts-fine-but-dies.html

------------
1995 Lexus LS400: Running Hot? http://whatisbyme.blogspot.in/2012/05/1995-lexus-ls400-running-hot.html

------------
2002 Toyota Camry: Puff of Blue or White Smoke while Starting? http://whatisbyme.blogspot.in/2012/05/2002-toyota-camry-puff-of-blue-or-white.html

------------
Multiple problems on car: Car runs hot, A/C blows hot and car starts surging? http://schematicsdiagram.blogspot.in/2012/04/multiple-problems-on-car-car-runs-hotac.html

--------------
Delay starting on Toyota Prius?

http://schematicsdiagram.blogspot.in/2012/02/delay-starting-on-toyota-prius.html
----------- Honda car will not start intermittently? http://technoanswers.blogspot.in/2012/02/honda-car-will-not-start-intermittently.html

--------------
Vehicle Starts, Runs and Loses Power http://whoisbyme.blogspot.in/2012/07/vehicle-startsruns-and-loses-power.html

--------------
Intermittent starting issues on Volvo 760? http://schematicsdiagram.blogspot.in/2012/02/intermittent-starting-issues-on-volvo.html

-----------
Car starts and cuts off immediately? http://repairhelpcenter.blogspot.com/2012/01/car-starts-and-cuts-off-immediately.html

-----------
Car won't start when cold? http://schematicsdiagram.blogspot.com/2011/12/car-wont-start-when-cold.html

===========
These details will help.
Thanks.

Electrical probblems are always the hardest to solve. I don't believe it to be the ecu, because when one fries it doesn't work at all but that may be the case. I believe from what you describe there is a short somewhere between an important censor and the ecu, like mas, 02 or throttle positioning censors. Ive also come across cases of which the catalytic converter was clogged making the car not operate correctly. Hope this helps.

power light flashing means trans sowas he able to retrieve any codes?check harness connections for trans in engine compartment,also wiggle engine harness in area between tran and engine bad groundf loose connection sounds like cause

Sounds like the radiator may need to be cleaned and bored. Under slow, in town driving conditions, the engine isn't working too hard. Long trips means the engine has to work a lot harder. If the cores in the radiator are plugged, the water can't get through to be cooled by the air.