MazingerZ

As above, I am experiencing hesitation at 4000+ RPM, I searched in here and found the usual problems with MAF failure or dirty Boost selenoid. I have done a MAF test (by unplugging it, the engine stalled) and just cleaned the Boost selenoid and lines with brake cleaner.

What do you guys think? What else can I check? I inspected the MAF and it looks clean and shiny...

The engine is standard apart from a 4.5" jap backbox

Your opinions would be greatly appreciated

cheers

Koji

saiklon

Fuel filter? My car used to hesitate on boost in the higher gears till I replaced the fuel filter.

Coils/plugs? Checked these as well?

MazingerZ

thanks for your reply, is there any particular procedure to check the coil packs and plugs? the fuel filter is less than 1 year old

dan83590

Remove plugs, re-gap clean and replace/buy new re-gap and replace. Coil packs should show no signs of cracking on the ends, but an undamaged coil could still be faulty.

MazingerZ

Morning guys,

many thanks for all your inputs!!!!

After cleaning the boost selenoid, the hesitation has reduced, certainly it is not there while in 2nd but there is some in 3rd..... hmmmm

will check the coil packs then...

cheers

Koji

dan83590

Don't overlook the plugs. They have to be just right to work well in the Impreza.