420a eclipse with p0351 code and p0420

[carlos505]

I'm new here so sorry if I do something wrong. I have already done research on here and the web and can't find anything. I own a 97 eclipse gs with 154'000 miles I have done maintenance regularly on my car I have a total of three codes a p0420 ,p0442 , and p0351 which is small evap leak , catalyst below threshold bank one, and coil#1 primary or secondary circuit malfunction. I can't find the evap leak if someone can point me to correct direction, as for the catalytic converter could it be the converter or o2 sensor I have never replaced neither of those. The p0351 is what worries me the most I have just recently replaced my spark plugs with ngk coppers two weeks ago , my wires were replaced no longer than 6 months ago with Bosch 7mm wires. I never replaced my coil. I checked for resistance according to chilton manual secondary resistance should be 11.5-12.5 and primary should be .5-.6 my primary is .8-.9 and secondary for me is 13.7-14.7, so could higher resistance give me a bad coil ?should it be replaced?

 

[92AWDHX40]

if its not in spec replace it.

 

[jayson427]

Try buying a new gas cap for the evap leak and a new coil since it's not in spec.

 

[Petergeralis]

Does it misfire? If yes you may have damaged harness when replacing spark plugs. Also check gap of plugs, secondary ignition problems could cause primary ignition codes. With evap leaks besides checking operation of purge/vent valves, or fuel tank pressure sensor it could have a vapor leak undetectable to your vision and need an evap smoke machine to find it.

 

[BigRed12]

Replace the coil(s). Higher resistance means less punch to try and jump the gap of the spark plug. So Replace it.

as for the evap, double check all over your tank for any leaks. I'm talkin' check everything from the cap, feed and return lines, to the seal around the pump assembly. EVERYTHING... be thorough.

Lastly, that pesky P0420. most likely the cat is clogged. and isn't doing its job anymore. SO to check, let it warm up to operating temp. Then (if you have one) take an IR thermometer and check the inlet and outlet temps on the cat. The outlet side should be about 100 degrees (Fahrenheit) hotter than the inlet. Also check for exhaust leaks, ie holes and such. Then check the o2 sensor (after the cat) for broken or loose wires. You can also check o2 sensor by back probing 2 of the wires (dont remember which 2 right off hand) and you should see a slight voltage fluctuation.