I'm about to embark on a tune-up (as much as I can with the tools I've got). I've changed plugs, distributor cap and rotor and coil before and had a mechanic friend change out the ignition wires but I am going to tackle the wires myself this time around (with the aid of a digital camera to help me remember where everything goes). Of course I will tag and number the wires as well. Anyway right now I have a standard set of AC Delco plugs (non platinum so I could re-gap them) and a Bosch cap, rotor and wires. The wires have about 45,000 kms and the plugs and distributor just under 20. Everything is running smooth however I do occasionally get some very minor roughness in the idle (and I do mean minor). In fact a mechanic told me it was nothing to be concerned about. So yesterday I pulled the plugs planning to clean and gap them and just replace the ignition wires. They were all uniformly white to whitish grey however the centre electrodes were worn (not terribly so but more than I expected to see with this kind of low mileage on them). All needed gapping (my under hood label says .035). A couple (#1 and #8 I think) looked a little odd in that the deposits were mostly on one side of the electrode. Is there a timing issue maybe? The under hood label says 0 degrees BTC. I have a Chilton manual that doesn't tell me anything about setting timing although I do have a timing light which I used to tune-up much older Chev and Cadillac carbureted engines. Also should I change all components at once? The retailer I used to buy these parts from (Delco and Bosch) no longer carries them apart from the plugs (soon to be discontinued as well) and claims the quality of AC Delco has suffered of late. What aftermarket components would be best apart from GM? I have mildly improved the air flow by way of a K&N air filter and a Magnaflow high flow single exhaust and converter. Gas mileage slightly better than stock but still appalling when compared to most vehicles on the road! I really don't care because I drive it infrequently (25% highway and 75% city) and it is an extremely comfortable ride and a reliable hauler and tow vehicle. Miles are low and condition mint (I still have people wanting to buy it even with these insane gas prices!) Finally the truck just barely passed its bi-annual emissions test and only because of the 'Italian tune-up' I ran for a couple of hours on the highway just before the test.
