well failing emissions is one good sign of bad cats...lol
you don't remove the temp sensor and don't have to remove anything to get at it.
there are many possible reasons for a missfire..start with the temp sensor and assume you don't have a missfire for now though if you put the wrong plugs in it certainly wouldn't help. You should be running the OE spec'ed ngk double platinums. If you aren't that could be part of your problem.
a fuel pressure gauge hooked up between the fuel filter and engine should hold pressure a long time after the engine is turned off. If pressure drops down quickly after turning the ignition off then you have a fuel leak.
Quote:
Originally Posted by James Scott
Michael: Thanks for the info...I couldn't remember ECUtune..ya!..That's it! Well, then:
1) I hate cats! I've replaced too many..and they're expensive. The main one has clogged twice I think..after banging on the ground [drop springs]. How would I know it's a cat problem? 
2) Can I get at the temp sensor easily..without having to remove the intake manifold? Can I get at it to remove if necessary also without removing intake M? So... I test ohms on a warm non-running engine with the connectors off?
3) Missfire??? You mean plugs? Could they need replacement after only about 15K miles? What else could I check that causes misfire? [Maybe it's burning oil??]
4) How would I know the injector(s) was (were) leaking?
Can I FIX something and then check just the idle HC emissions somewhere (smog station or regular mechanic?) before spending another 40 or 50 bucks to perform smog test (and risk referree)? 
Thanks for your help! Jim  |