I went last week to check what codes I got for a Check engine light. Had that light for while on my dash. I know I have a vacuum leak which I am still trying to finish.
Here is a list of the codes I have:
p0171
p1310 misfire 1 cylinder twc damage
p1310
p0301 cylinder 1 misfire
p0304 cylinder 4 misfire
p0300 random misfire
p0730 incorrect gear ratio.

What should I do to clear all these codes? I replace my sparkplug about 7 months ago but not the wire,distrubtor and cap for the sparkplugs. Should I replace all these as well? should I replace the 02 sensors? Also how do I clear a vacuum leak. any suggestions would help?

 

Being a '95 you might have an under hood diagnostic panel that will reset codes and the OBDII port on the center console. You should use one or the other to reset the codes and shortly after the CEL comes back on have it re-read to see what codes come back.

What do you mean by you're trying to "finish" a vacuum leak ??

Pull the cap and rotor and visually inspect them for carbon tracking, dirt and moisture. Replace if in doubt.
With the wires, if they physically look cracked, feel brittle or have any damage ... replace. In the evening when it's a little dim or dark use a spray bottle with water and a couple drops of soap to spray the wires and look and listen for the wires to be arching to ground. It's a cheap easy test.

 

Thank you for the reply. I meant to say I am still trying to fix a vacuum leak and clear the code p0171 associated with it. I bought a new spark plugs(VOLVO OEMS) Bosch spark plug wire, Bosch spark plug Cap and distributor. I want to replace the entire spark plug since I have not done this since I got the car last year.

After I replace the sparkplugs and all the associate parts, is there anything I need to do to make sure it's tune so it wont misfire again? Also this vacuum leak is a real pain and I am trying to fix it. I keep seeing PCV needs to be done a lot here in this forum. Would doing this plus replacing the manifold gasket help with this. I also have some oil puddles under my spark plug cover. I will post pictures of it soon on here.

Any tips or info would help Thank you.

 

Do you know where the vacuum leak is ?? A vacuum leak can cause a misfire too by causing the mixture to a cylinder or more to go very lean.

Replacing parts doesn't guarantee it will solve the problem. The parts you are replacing are the likely cause but inspecting or testing them is what tells you their condition and what problems they might be causing. They are all maintenance items so if you're unsure when they were done or if they're still good it's best to replace.

The oil is one symptom of having a clogged PCV system or a bad hose. If it's clogged or restricted it can allow for pressure in the engine and then that pressure pushes out oil. The oil under the plug cover is likely coming from the oil fill. It could just be a bad gasket but if you test and there's pressure a new gasket isn't going to help.