Step by Step Tune-Up instructions/3.5 94 LHS

Hello Everyone, I've been lurking for about 2 weeks now. I've been trying to find step by step instructions on tuning up my 1994 LHS. It has the rough idle syndrome I've seen described on here. I just bought it off of eBay for $500 and it needs a bit of work put into it. I've bought the intake manifold gasket just in case that needs to be changed but I would like to start with the tune-up first to see if it goes away. Does someone have or could point me in the direction of instructions on how to properly tune-up my car? Thanks in advance for your help. I'm sort of a newbie(having not done any work alone but have helped before) when it comes to car mechanic work, but would like to learn so any help is appreciated.

A tune up is pretty straight forward, change the plugs and wires (remove the plastic "3.5L 24 Valve" intake cover and you will get more room for snaking the new wires under the intake plenum), replace the air and fuel filters, change the oil and filter if it's due or hasn't been done yet in your ownership add a bottle of good fuel injector cleaner to the fuel and take it for a drive to see if it clears up.

Chances are if the miss is just at idle and the engine seems smooth any other RPM then it would be a good idea to do that intake manifold gasket replacement since the 3.5's are known for them leaking after time.

A tune up is pretty straight forward, change the plugs and wires (remove the plastic "3.5L 24 Valve" intake cover and you will get more room for snaking the new wires under the intake plenum), replace the air and fuel filters, change the oil and filter if it's due or hasn't been done yet in your ownership add a bottle of good fuel injector cleaner to the fuel and take it for a drive to see if it clears up.

Chances are if the miss is just at idle and the engine seems smooth any other RPM then it would be a good idea to do that intake manifold gasket replacement since the 3.5's are known for them leaking after time.

Thanks, I appreciate it. It does run pretty smooth when I have it running at higher RPMs. How hard is it to change the intake manifold gasket?