i have a 1994 gmc sierra and only when going up hill it starts to sound like a spark knock then it will spit and sputter almost like it is running out of gas, any ideas is appreciated
If you use the low octane gas all the time try using the middle or high test gas. Also check air filter and replace if necessary and replace fuel filter if have not done so in a while
i do need to replace the air filter and fuel filter for sure, and i do use 89 octane in both my trucks.
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