HT4100 4.1, 4.5, 4.9 Discussion, Tune-up questions, spark plugs in Cadillac Engine Technical Discussion; Hi,
I am planning to get a tune-up soon. A guy at Advanced Auto Parts recommends AC-Delco Iranium plugs for ...
I am planning to get a tune-up soon. A guy at Advanced Auto Parts recommends AC-Delco Iranium plugs for my 4.9L, but the mechanic I might go to says AC-Delco Platinum plugs are better. Also, the shop suggests cleaning my fuel injection system, even though I normally run Premium octane and put injector cleaner in every so often. My last two tanks of gas have been mid-grade, however. Is that likely to foul my injectors? And what about a K&N air filter?
Any AC Delco plugs are fine. I'd go with the platinum because they're reasonably priced. I believe the iridiums are more expensive, and you really won't see much of a difference.
Even the AC Delco regular plugs are great for under $2 a piece, but your car came with platinums, so I'd put those in there.
Running mid-grade won't clog the injectors, but it could harm your motor if you hear pinging. The 4.9L engines have no knock sensors (unlike many other modern motors), so you're best to fill it with premium.
An injector service is fine, but I wouldn't say that you absolutely need it.
Well, it`s finished! The plugs, wires, distributor, and rotor were all replaced, and the air filter was cleaned. The fuel injectors and throttle body didn't need service, which saved some money. Some Lucas oil stabilizer was put in. Now, my oil was due for a change in about 250 more miles. Should I go ahead and change it or wait a few hundred more miles? I will also have to replace my catalytic converter soon; more on this later.