I have a 2000 s10 with a 4.3 vortec I keep getting a p0303 cylinder 3 misfire I've replaced computer spyder with injectors map mas idel air cap roter wires the works help very frustrated
Compression test cylinder number 3. If it tests low that's why it's misfiring. Could be a burned valve, worn piston rings, or possibly a blown head gasket. HTH. -Jim
That was my assumption to so I cracked the heads off took them to my buddy's machine shop and sure enough Cylender #3 had the worst problem with the valve seats cracked in half.There were also 4 others that were bad. So I'm having a valve job done and having all new valve seats put in. Valve job $360 Fel pro head gasket set $50 new head bolts $25 miscellaneous $60 So for $500.00 it'll be like brand new. Now he had 6 other shops try to fix this for a total cost $1700 and none of then seceded. In closing just goes to show that paying a $90 per hr shop rate isn't always the way to go. Just a simple compression test that took maybe 20 min sese it all. Thanks Jim Troy R
You're welcome Troy. Glad to help. -Jim
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