[JKLNHDE]

I am new to the forum and own a 93 Deville Touring Sedan with a 4.9 ltr. V8. The car has 70k miles and needs a tune-up. My question's are:

1-Are any special tools needed to change the spark plugs in this car? Any advice is appreciated should the procedure deviate from normal. I am concerned about changing the 4 plugs against the firewall. Dealer wants $200 to change these-what a rip.

2-Fuel injector cleaning. What's the best stuff to use? Dealer says that during "thier" tune-up procedure, they add an additve to the tank (2-3 cans of something). IS the GM additive different than an off the shelf injector cleaner available at a regular parts store?

3-Ignition. I am unfamiliar with the ignition on this car. During a tune up procedure, do you recommend any parts be replaced on the ignition system?

Thanks for your help and advice regarding anything else I should consider looking at while I've got this thing apart. I am the new second owner and I have no idea what's been done/has not been done to this car.

 

[Katshot]

1. No special tools req'd.
2. A product called "Run-Right" is very good. The stuff you put in the gas tank is mainly "preventive" in nature, not much good for actually cleaning dirty injectors.
3. Tune-up should involve ALL ignition secondary components as follows:
Distributor cap
Rotor
Plugs
wires
Obviously, some cars are DIS so therefore omit the cap/rotor.

 

[Ralph]

I would also do the fuel filter and pcv valve. As for the sparkplug wires, I thought they lasted past 100,000 miles?

 

[Katshot]

He specifically asked about the ignition system. That's why I limited my comments to that system. There ARE other parts that should be done at that time though.

 

[Qristofer]

I have been trying to change the spark plugs on my deville and trying to reach the rear 4 plugs is a feat in itself. I have all but given up on it. Also changing the cap and rotor is close to impossible because its all incased in a box like unit. I just gave up on it. I want to hear from someone that has changed the plugs on a 4.9L and what kinda tools are best to use.

 

[Katshot]

I always just used a stubby 3/8ths swivel-head ratchet and a swivel plug socket w/1" extension as I recall. Probably a full-size plug ratchet to break it loose though.