Since having my 96 Turbo serviced which included an k@n panel filter,new plugs and Jap innovations backbox I have been experiencing a random slight hiccup or missfire at low revs. Before the service it was happy to pull away in 2nd or while in traffic just slipping the clutch in 2nd but now occassionally it has a slight hiccup before it pulls away, usually after I have been stationnary a while and the engine is hot - although it is a random event. Doesnt seem to have a problem once youre accelerating - just when your sort of labouring the engine. Checked the coilpacks during the service and no sign of cracks etc, and the plugs were gapped at 7mm and bought from the Subaru main dealer.
My first thought was the de resticted back box could be effecting the breathing.Any ideas about what it could be would be much appreciated.

 

Has no one else experienced this then when changing backboxes

btt

 

Mine developed the same symptoms.....after I disconnected the battery. I cleaned the terminals with a wire brush and reconnected and it went away.

I only remember becuase 2 days ago I gave some bloke a jump-start, and on the drive home mine was doing it again. So I will be doing this 10 minute job on the weekend!

Good luck!

 

wirerob, could be something to do with the 7mm plug gap

sorry, had to say it

 

A lot of intermittent misfires are caused by plug leads breaking down, or not being refitted properly. Scooby plug leads are not the easiest to get off!
Mine did this sort of thing for ages b4 we finally traced it to one plug lead.

 

my scooby dosent have plug leads it has coil packs on top of each spark plugs is this normal for a scoob? its a wrx 95

 

Yes this is perfectly normaly for they MY of your car.

 

Thanks for all the replies. Last night I took all the plugs out and checked the coil packs again. They appeared ok with th epception that the two nearside packs had perished rubber bungs on the end. I intend to replace these, but for now have taped them round with insulating tape. Put it all back together and took it for a run. It was great until the engine warmed up - I was just congratulating myself when the car started misfiring badly and losing revs. Crawled home got it in the drive - ticked over perfect. Took it for another run and all was well, as it was this morning going to work. All I can think is that water may have leaked from the washer bottle when I removed it and has somehow found its way onto the coil packs - otherwise I am baffled. Car did seem down on power though this morning, might be pyschological though as I was so nervous of pusing it incase the thing died in traffic.