I bought my Corvette a couple weeks ago. It's an 89 Coupe. I was looking at the plugs today and they look a little rusty. I would like to change the Plugs and maybe the wires while I am at it. The car has 43K miles and seems a little ruff at idle.

This is my first Corvette and I am not sure what it should feel like when at idle. It seems just a tad rough. Almost like a bigger cam, but I am sure it is stock.

My question is: Would it hurt to hit the plugs with some PB's and let it sit for a couple days, or should I just see if they come out normally ?
I am not sure how PB's reacts in reguards to Aluminum and don't want to damage anything.


Thanks.

 

Give the easiest one to reach a try when the engine is cold. If you just bought the car you should give it a tune up (plugs, cap and rotor, pcv valve, air filter, clean the throttle plate area, check the throttle position sensor adjustment, change the wires if you can handle it) and change your fluids. While your working on it give a little wipe here and there to clean things up. Put a little protectant on the hoses, vaccum lines and black rubber and plastic items to brighten things up. Take your time and have fun with it. I'm sure others will chime in with other things. Stock idle should be fairly smooth.

 

Welcome to the Forum and congrats on your new '89 vette. It's one of my favorite years for L98 and C4s.

Your '89 has Al heads so the plugs should come right out and they have anti-seize on the threads. But it won't hurt to the Al to use PB Blaster, it comes handy in nuberous places.

The 1-7 plugs are a snap to access but the 2-8 set are a different story. To help with the latter:
-remove the rear brace to the A/C compressor, the two AIR hoses, the oil dip stick and the access panel in the right fender well.
-use a socket with extensions and swivel on #2 & #4 plugs, the socket only on #6 and the socket with an open end wrench on #8.
-use a little anti-seize on the spark plugs
-a thin film of dialectric grease on the spark plug insulator end will facilitate installing the wire boot

TPIS makes a nice set of performance wires that look stock, fit the stock looms and have much lower resistance than the stockers.

While you are under the hood remove the "frisbee" disk from the front of the water pump pulley to free up 10chp:
-remove the serpentine belt
-remove the frisbee
-install thick lock washers behind the bolt heads and attach the water pump pulley
-install the serpentine

The rough idle could be caused by several things, but cleaning the intake and IAC are a good starting place. Though your TPS is not adjustable, the method to set base idle after you clean the IAC is on my site.

You might also check to see if all the vacuum hoses are connected and in good condition.

Enjoy your Vette and save the wave.

 

Thanks for the info. I love the car so far. I have wanted to own a C4 from the first day I saw one. I will do all of the above. Thank you all for the free flow of knowledge here. It's the best.

 

The engine is pretty clean. I do want to change all the fluids and I ordered some new mufflers to put on it till I can do true dual exhaust.

here is a pic of the motor

 

hey thets a clean tooking ride, congradulations. just don't forget to wave.