Cruising Speed Misfire/Constant Knock Retard

Jan 17, 2006 2 Replies

Hello



Pontiac Bonneville 97



3800 II NA
130k miles

Symptoms:


1) Idles poor, always
2) Somewhat consistent multiple misfiring issue, cruising speeds. Occassionally at idle or on freeway.
3) Once it's warm, Knock Retard from .5 to 9 degrees, irregardless of speed. EXCEPT, not under WOT

Replaced Fuel Filter/Sender/Pump, Switched injectors, new plugs/wires/coils, MAP, TPS, cleaned w/GM engine cleaner thru intake, ran oil cleaner, fuel cleaner



NO CODES



LT Fuel Trim Mostly Rich, ST Tends to be Rich



Any thoughts??



What are you seeing for vacuum readings? How did the old plugs look? Timing steady?

Steve W.

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