3.0 Idle Issues

[ucosmin]

Hello Suburau Owners.

My names is Cosmin and I'm from Romania, my english is not very good so please bear with me. I've recently bought a Subaru Legacy 3.0R with 5EAT transmission and I have some problems with it. The car is made for the Saudi Arabia market and has 98.000 km on it.

First of all I've searched the forum but I didn't find any info that might help me. I'll try to explain the problem. A few weekes ago, at a stoplight with the AC on and the tranny in D mode, brake ON, I felt something like a missfire. From thereon at every stoplight the "missfire" was present. Later on the "missfire" occured even if I had the AC OFF and the tranny in N or P. A few days ago it rained like it was the end of the world and the "missfire" was present until the 1500-2000 RPM, after that everything was ok. I never had a CEL light ON. I went to a shop and did the following: changed the sparkplugs (NGK Iridium), replaced two coils because they were cracked and checked the injectors. The old sparkplugs looked well, they we're all red/orange like they we're all firing without problems. After replacing the two coils there was no improvment. After checking the injectors the engine has a very rough idle and it sounds like it runs on 4 cyl instead of 6 even at higher rpm's. The butterfly\acceleration throtle body was cleaned. After al these things done there is no improvement and no CEL light. I even disconnected a coil while engine was idling and the CEL light didn't came on. Can you give me some advice?
Here in Romania the 3.0 engine is very rare, most of the Subaru cars have de 2.0 or 2.5 and the serviceshops don't really know this type of engine.

Thank in advance and again sorry for my not so good english.

[patrickbateman]

Out of interest, have you tried an ECU reset?