have a forester 02 with 120,000 started to mis at idle but ran better at 2500 rpm. error code showed 3 and 4 misfire, put on new plugs, Bosch, ran perfect for two weeks then started to run rough at idle again, replaced wires runs good at higher rpms but still idles rough and lacks power. today I checked ohms at coil and show 14 across 1,2 and 3,4. I see that this is not something new but looking for advice. thx.

have a forester 02 with 120,000 started to mis at idle but ran better at 2500 rpm. error code showed 3 and 4 misfire, put on new plugs, Bosch, ran perfect for two weeks then started to run rough at idle again, replaced wires runs good at higher rpms but still idles rough and lacks power. today I checked ohms at coil and show 14 across 1,2 and 3,4. I see that this is not something new but looking for advice. thx.

 

That happened to me too and the dealer told me it was probably a timing problem. They had my car for 2 days and 700$ later it comes out with a new throttle positioning sensor. Might be worth a try.

If it only misfires when warm, not cold, and if you have not replaced your front 02 sensor in the last 40k miles....then try replacing it.

You might try a new fuel filter. A plugged/dirty one will throw a injector mis-fire code.

It's been stated on here many times to use OEM plugs/wires, so maybe worth a shot....esp. since it worked for 2 weeks...me thinks the Bosch just didn't like their new home.

 

Try some NGK plugs, and let us know.

 

GL,

Td

It's been stated on here many times to use OEM plugs/wires, so maybe worth a shot....esp. since it worked for 2 weeks...me thinks the Bosch just didn't like their new home.

 

Try some NGK plugs, and let us know.

 

GL,

Td

 

Yea, it worked for two weeks.

 

"Sometimes the Check Engine Light illuminates because the computer detects misfires. Subaru released an improved spark plug wire set to solve the problem. The ignition coil should also be inspected for carbon tracks or short circuits between the contacts."

wait wait..

 

What bosh plugs are you using?? i hope its not the platinum plugs.

It's been stated on here many times to use OEM plugs/wires, so maybe worth a shot....esp. since it worked for 2 weeks...me thinks the Bosch just didn't like their new home.

 

Try some NGK plugs, and let us know.

 

GL,

Td

 

 

loong time ago when I had my forester before I knew better I installed bosh plat plugs in the car.. that car would misfire so much it was beyond stupid.. So I went ahead and swapped out for NGK I think coppers or whatever for the 98MY anyways car ran MUCH better.

Either bosh plats are complete garbage, or they don't like subarus. I put a set in my car (before I knew better) and within two weeks it ran like crap. I was actually 500 miles from home at the time. What fun. Anyway when I got home I pulled the plugs out and they all looked like this.

Nuff said. Use OEM.

 

Wow never seen that but maybe its the wasted spark setup that makes it run like poo?

Thanks for all the input! Yes I swaped back to NGK a little better put still rough,

runnning Seafoam now fuel filter and o2 sensor are next and looking into OEM plug wires. keep you posted.

Wow never seen that but maybe its the wasted spark setup that makes it run like poo?

 

A lot of cars use a wasted spark system. It's not unique to subaru.