p0305 code cylinder #5 misfire on 2002 Mazda MPV

2002 mazda mpv 3.0 i have a p0305 code i interchanged the coil and still got the code. but what i noticed i disconected each coil one at a time at idle rpm (700) and every time i disconected one the engine would shake exccept when i got to # 5 nothing would happen when i incremented idle speed i disconnected 5 again then i noticed change in engine. I think its a clogged injector please advise.

by in Hayward, CA on April 21, 2011
Get Your Car Fixed at a RepairPal Certified Shop.
We certify shops based on expertise, quality work, and verified customer reviews
1 answer
ANSWER by , April 22, 2011
It could be the plug or injector. You should check to make the head is not cracked. (common problem and with this cylinder) Do a pressure test on the cooling system and a block test to make sure it's not a cracked head before spending any more money.