I'm trying to help a friend with '96 Legacy, 2.2 liter Automatic with approx. 55,000 miles on the odometer. The car is located in the Virgin Islands. The problem is the car begins to miss when approaching the top of a steep grade. This is a real problem in Islands since all roads have extremely steep grades that you eventually have to climb, no getting around them. The problem is intermittant and usually results in the Check engine coming on. The miss goes away once the hill has been crested, only to re-occur on the next steep hill. The max. speed limit in the Islands is 35 mph, so the car is usually not reving more than 2000 rpm at the time the problem occurs. Downshifting to a lower gear doesn't help. The weather in the Islands is usually warm (above 75 degrees) and humid.

 

A local machanic and the Subaru dealer in St. Thomas (yes there is one) have spent numerous hours trying to resolve the problem with limited success, the following has been done:

 

Spark plugs, air filter, Ignition Coil Pack, fuel filter and spark plug wires (labeled "Arnley Worldparts Premium high temp silicon mag core") have been replaced, the fuel pump pressure has been checked, the gas intake screen in the gas tank has been cleaned. Premium gas has been tried, Techron has been added to the fuel.

 

The problem went away after the spark plug wires were replaced only to come back about 1000 miles later. After the new occurance the dealer claims the error code indicated #2 spark plug was misfiring and replaced only the wire to #2 (new wire labeled "Yazaki R-16-AIPS-2, #5270"), it didn't fix the problem.

 

I suspect the problem is still spark plug wires, either the set the dealer put on are the wrong part, low quality or defective. But before recommeding replacing again I wanted to see if anyone had any better ideas, or a suggestion on a brand of plug wires. I saw one thread that recommmended Magnacor wires.

 

Any help would be greatly appreciated.

Similar to symptoms of a bad/plugged catalytic converter. Usually feels like a loss of power under load.

maybe some kinda fuel starvation? weak fuel pump?

If the wires (I suspect coil pack at the same time) made the problem go away I think that is close to the problem. The #2 misfire is your biggest clue. Try the free / cheap things first. Pull the #2 plug and check the tip to make sure it is ok. Try swapping a working wire from another one of the cylinders and see if the misfire code follows the wire - indicating the bad wire. If this does not work check the coil resistance, however it may only be failing under load - you have any friends with subarus you could try swapping coils for 10 minutes? It may also be a bad injector or weak fuel pump - the pump does have to work harder to pump gas to the front of the car which is higher going up hill - ever try going up a hill in reverse and see what happens - If it was fine I'd say it's your fuel pump for sure, as the car is under the same load just going up backwards that gives the fuel pump a height advantage. Let us know what happens...good luck.