Rough Idle and Rattling

[Blue]

Whats up,
So I just bought an 87 hardtop GN and it has this rough idle. At full throttle it does fine.
The mass air flow sensor has been replaced recently.I'm told that it could be caused by bad spark plug wires, I don't think that they have ever been replaced.

There is also a rattle that occurs occasionaly. It comes from the lower passenger side.
My friend told me the rattle is probably the heat shield or the catalytic converter.
I'm also told that the rattle could be setting off the knock sensor and thus retarding the timing.

What do ya'll think?

 

[smokin'6]

Best bet is to pick up a Scanmaster and verify all your sensors are set correctly, it will also tell you if you are even registering any knock.

 

[TurboBuckeye]

You should probably do a full spring cleaning including new wires and go from there. Don't forget the role the chip plays in how a car idles and runs also.

And buy that Scanmaster a.s.a.p. as Smokin'6 said

 

[Blue]

I changed the plugs, that seemed to help a little.

How do you get this Scanmaster thing, is it a special order?

Also the car has been idleing at around 2000 to 3000 rpm. After cutting it off and on the idle returns to normal. Any ideas?

-Blue

 

[rodman99999]

Scanmaster

On the home page of this site, under our sponsors, you'll find 'Full Throttle Speed'. They sell the Scanmasters. The price on eBay is $249.00. It's a small unit that can be mounted above your heater controls, or on top of the dash(easy visibility). It's nice to have the info from your ECM available all the time, though what this unit gives you isn't as comprehensive as a Turbolink, or the other laptop based data loggers.