Tune up

[zstahler]

Best spark plugs for a 1993 chevy c1500 4.3 v6

 

[Schurkey]

Whatever the service manual calls for. You can pay more money, but it's not like you'd be getting a significantly "better" spark plug. ACDelco or NGK are fine by me. Nippon Denso is OK. I used to like Autolite before they moved production to China all those years ago. I quit buying Champion plugs--soft, fast-wearing electrodes, and the most brittle porcelain in the industry--more than thirty years ago. I don't buy Bosch anything on general principle--Bosch bought and then destroyed the OTC tool company, left me holding the bag for what had been a "Lifetime Warranty" floor jack.

I really like Iridium plugs in vehicles with port- or in-cylinder fuel injection and no history of oil-burning or plug-fouling. But I don't really see the benefit in a TBI engine due to the relatively poor fuel distribution. The main benefit of Iridium is the very long service life...and that sort of service life is just not realistic with TBI, and even less-so with a carburetor.

Don't forget all the other "tune-up" parts and procedures. At least test/inspect the cap, rotor, plug wires, PCV system, EGR system, EVAP system, heated air intake system. Replace the fuel filter, check the air filter. Make sure the ignition coil will reliably jump the gap of a spark-tester calibrated for HEI; preferably after the coil is hot from driving around for half-an-hour, and with the top of the coil misted with water from a squirt-bottle. Verify initial ignition timing, and the electronic spark advance. And any O2 sensor older than 50K miles or a few years is due for replacement.

Then connect a scan tool, verify ALL the sensors and computer outputs. Assure fuel pressure is adequate at prime, at idle, and under load.

 

[Erik the Awful]

Generally speaking:
GM - AC Delco
Ford - Motorcraft of Autolite
Chrysler - Champion
Japanese or Korean - NGK or Nippondenso
German - Bosch
Italian - Magnetti Marelli
British - BWP or Bosch

NGKs tend to run well in anything. I quit putting Champions in my wife's Chrysler 300 and started using NGK and eliminated a lot of misfire.