Engine codes; suggestions.
 

I have 3 SES codes:
P0304 - Cylinder 4 misfire
P0171 - System Lean (Bank 1)
P0102 - Mass or Volume Air Flow Circuit Low Input

I think the misfire could be due to the previous owner using Bosch plugs & wires. (I took it from a search on this site that that is bad) Should I replace the plugs & wires? Or, just the plugs?

I'm assuming the System Lean (Bank 1) is the O2 sensor before the cat?

I haven't had a chance to to the MAF/TB cleaning methong in the tech info yet.

I just want to make sure I'm on the right track here...and suggestions would be greatly appreciated.

Plugs and wires could very well have everything to do with your codes. So could a failing upper manifold and/or failing lower intake manifold gaskets. (I had those codes come up on my 96 after I did an upper changeout. It was because of the buring coolant fouling out the plugs, and taking out the O2 sensor).

I just bought this car a month or so ago...it started throwing codes after I had it a week. Just last week, I had a new intake and LIM installed. Swapped out the dex-cool for the unirversal stuff.

I didn't check to see what the codes were until after the new intake was installed. (I planned on the UIM & LIM before I even bought the car) I'm thinking I should replace the plugs, wires, and O2 sensor...then have the codes erased and go from there.

Having experience with P171, I can tell you it's 100% NOT the o2 sensor. It is the O2 sensor that is telling the pcm to add fuel due to a lean condition, the PCM is telling you it is adding more fuel that the acceptable programmed parameters. Hence the code.

One fo the diagnostics for P0171 is to check the MAF. You also have a MAF low voltage. I'd head toward the MAF cleaning/replacement, clear codes and see if either MAF or Lean bank come back.

Cylinder 4 misfire. It sounds like you are due for a tune up. Perform the tune up and check the resistance on the posts for the coil labeled 4/1. You should see something in the 6.XXX range. If not..the coil and a tune up are needed.

Please continue in your other topic about codes instead of starting a new one.