CliffA
New Member
first post from this newbie....i have done a quick search of this forum's archives but did not find any info relating to this issue...
for background info I am a pretty good shade tree mechanic....I have been wrenching on vehicles and boats for the past 45 years or so as a hobby....got started working on muscle cars back in the 70's.....
I recently bought a 2005 Silverado 1500 (127K miles) with a 4.3 vortec engine, 4 speed automatic tranny, 2 wheel drive, and standard cab and standard bed...it has base trim...it will be used mainly as a commuter vehicle with some light hauling off and on...
I am going through the truck now correcting the hack job the previous owner had done to the wiring and electrical systems....also having to replace several interior panels because the PO broke the securing clips when he yanked the panels off....
......also tracking down and correcting the rattles and squeaks in the cab....
one item I am trying to address is spark knock when I am accelerating aggressively or going up a hill...I do not have any trouble codes stored in the OBDll system...I have replaced the spark plugs and the wires, new distributor cap and rotor button, cleaned the throttle body and MAFS, and have reset the computer.....I have also changed both upstream oxygen sensors...my engine does not have an EGR system....it has an 'X' as the 8th digit in the VIN which indicates there is no EGR system....I have not tested the knock sensor since I don't know how and can't really get to it due to its location on the top of the engine behind the distributor....I have tried using 93 octane gas but I still get the spark knock....there is no knocking when I am cruising on fairly level ground and when I accelerate smoothly from a stop light....the knock only happens under load going up a hill or if I accelerate aggressively....
any ideas what I can check next?
Thanks.....
Cliff
for background info I am a pretty good shade tree mechanic....I have been wrenching on vehicles and boats for the past 45 years or so as a hobby....got started working on muscle cars back in the 70's.....
I recently bought a 2005 Silverado 1500 (127K miles) with a 4.3 vortec engine, 4 speed automatic tranny, 2 wheel drive, and standard cab and standard bed...it has base trim...it will be used mainly as a commuter vehicle with some light hauling off and on...
I am going through the truck now correcting the hack job the previous owner had done to the wiring and electrical systems....also having to replace several interior panels because the PO broke the securing clips when he yanked the panels off....
......also tracking down and correcting the rattles and squeaks in the cab....one item I am trying to address is spark knock when I am accelerating aggressively or going up a hill...I do not have any trouble codes stored in the OBDll system...I have replaced the spark plugs and the wires, new distributor cap and rotor button, cleaned the throttle body and MAFS, and have reset the computer.....I have also changed both upstream oxygen sensors...my engine does not have an EGR system....it has an 'X' as the 8th digit in the VIN which indicates there is no EGR system....I have not tested the knock sensor since I don't know how and can't really get to it due to its location on the top of the engine behind the distributor....I have tried using 93 octane gas but I still get the spark knock....there is no knocking when I am cruising on fairly level ground and when I accelerate smoothly from a stop light....the knock only happens under load going up a hill or if I accelerate aggressively....
any ideas what I can check next?
Thanks.....
Cliff
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