l ran bosch platinum 4 series plugs in my monte for 4 months and the other day l replaced one plug on the rear passager side with an ac delco plug (been procrastinating on replacing the other 7 for the last week or two). now its ticking from that one plug, l know because if l unplug that 1 spark wire the ticking stops. ive replaced all spark wires, put the old bosch plug back in and checkd for spark from the distributer cap.
what could be causing the noise and lack of power?
i noticed that the plugs that come from that 1 cylinder are always wet around the threads and kinda dark at the tip (could be carbon build up) but l didnt really smell any gas.
the ticking goes faster when l accelerate and l also notice a hesitation at take off too, like the engines about to conk out and then it moves.
i dont think its the valves ticking because the ticking stops when theres no spark runing to that cylinder, and l figured valves would tick regardless... please give me honest feedback before l go and let a mechanic rip me off over unnecessary head work....

What ur hearing & feeling is an arc. It is where the voltage is ground out to a chassis ground before it gets to the sprak plugs.

Common causes r arcing plug wires (broke down, worn wires that lets spark jump from wire to valve cover, engine block, exhaust)

Or a cracked spark plug

Or a cracked dizzy cap

Wait untill night time, turn out all lights, fire engine up, & open hood.

Bet u will see a blue flash, flash, flash, each time u hear the tick. See where flash comes from & u know what the prob is

could be a cracked valve in that one cylinder, get a compression tester, rent one or buy one for 20.00 or so, pull at least 3 plugs on that side of the engine & see what the readings r , u may hear a valve, another thing u can do is when its dark spray water from a spray bottle around the area of that plug & wire & see if u see arcing spark maybe cracked plug wire or plug make sure ur wires r all in the correct order & none of them r hooked up to the wrong plug compression test will tell u whether its electrical or internal valve or piston ring, a repair manual will explain what compression reading or a good range, if the cylinder next to the one u expect a problem is the exact same reading ur head gasket may be the problem

Check if u got the right spark plugs (engine can be sensitive to difference/missing of one alphabet/numeric the spark plug specified)

Check if the spark plug is defective by, first swapping its location with the next spark plug

If the same observation is repeated by that suspicious spark plug, it can be confirmed to be defective for replacement spark plug

If the subsitute spark plug shows the same result, check the spark plug wires (likely to be over-used service life). Replace spark plug wires & monitor (you may need a Vehicle Electrician)