Rough idle when cold - Saabnet.com Bulletin Board
‘08 9-3 2.0T. Last fall engine started running increasingly rough when starting cold, fine otherwise. In Dec., 87k mi, CEL came on – P0304, misfire on cylinder #4. Reset CEL.
• Replaced spark plugs with NGK PFR6T-10G gapped to 0.035 in.
• Replaced ignition coil on cylinder #4.
• Added 20 oz. of Techron II to fuel tank.
Jan, 89k, CEL is on. Code P0304 again. Took car to local indie.
• Checked compression hot: #1-155, #2-155, #3-155 and #4-150. Did cold leakdown test: #1-165, #2-170, #3-170 and #4-80. Indie called other shop who recommended cleaning valves. Added one can of BG-44 cleaner into intake through vacuum line near fuel pressure regulator. Also added can of BG-44 to fuel tank. Recommended continued use of BG-44.
Jan, 90k, CEL came on again and went off 2 days later. Still running rough at cold start; fine otherwise. Added BG-44 to full tank of gas
Apr, 94k. Still running rough at cold start, fine otherwise. Less so in warmer weather. CEL has remained off.
Is this likely the “valve wear” discussed in earlier posts, or something else?
posted by 98.245.15...
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