In an ironic twist of fate, as I was taking a picture of my gauge cluster for the purpose of showing you all that a 2gnt can actually survive without a CEL, I get a CEL not 30 seconds later. I kid you not.

I had the EGR code a week ago, and I fixed that. A whole week with no codes. Went in to get smogged yesterday - Failed hydrocarbons at the 15mph, but passed at the 25mph speed. He said it was misfiring a little (which has been happening recently but not that bad, and I didn't expect it to fail smog for that reason), so I figured I'd replace the plugs in the next couple days and retest.

P0420 translates to a failing cat. It's a RRE racing cat, less than a year old. Perhaps it could be the sensors (both my O2 sensors are 10 years old with 140k on them). What's the best way of testing this? Or do I need to buy some r3515t0rs

Replace the upstream sensor.....my god 10 years old. Just replace it, your gas mileage might improve as well.

i will NEVER move to an emissions testing state

Originally posted by 420agreenvilleSC
i will NEVER move to an emissions testing state

I agree %100, They got rid of it years ago here in ohio. Even my first car when I was 16 (over 4 years ago) had e-check paperwork with it but I believe even then it was already gone.

EZ,

Consider buying an Innovate LC-1 if spending money for a new O2 sensor. the digital controller has narrow band and wideband outputs to satisfy the stock ECU as well as a gauge and standalone/piggyback. I have been using one with my MSnS for 3 years now and I love it.

I think the P0420 is the longest living code in my computer as a testpipe was one of my first mods back in 2002 :p

Thanks guys. Prolly will change the front O2 sensor (hmmm, must research and find the inexpensive sensor options again...). As far as the LC-1, I already have the AEM wideband and I love it (plus it currently outputs the A/F signal to the emanage which charts it over time - VERY USEFUL setup IMO) so I don't want to switch at this point.

As far as the misfire, I understand that SEVERE misfire can damage a cat very quickly because the fuel dump will melt the coating off the cat surface. But this was very light misfire for a brief amount of time. I hope I haven't ruined the cat already, but we'll have to see.

Damn, just sold one of my 2gnts yesterday, and there I was thinking that my problems will now be cut in half. But no, the DSM gods demand that I must perpetually work in the garage.

Originally posted by CODE4
I think the P0420 is the longest living code in my computer as a testpipe was one of my first mods back in 2002 :p

you know it's funny, I've been running a test pipe on both my cars for years now and it's still never thrown a code for it.

hooray P0123 popped up today. And nothing in the archives here on 2gnt about that.

but from http://www.obd-codes.com/p0123, this is a TPS issue, and is associated with hesitation. damn

you're having all kinds of great luck man.

Just ran an errand and both codes disappeared. Misfire seemed to be reduced if I drive like it's a wheelchair. One of my BOV vacuum lines is butting against the TPS wire, but the connector is on solid. I wonder if this is happening: engine vibration->wiggling the TPS connector causing an intermittent loss of signal->misfire->dumping fuel onto cat-> causing rear o2 sensor to have a fit.

it's possible. I've seen stranger things at work.

I live in an emission controlled state but it only affects 10 or 15 counties. I happen to live 5 miles outside the county line and I don't have to register for emissions :P

Both codes reappeared. Damn all of you that live in non-emissions states :bash

Other things to consider:

If you're only going to use it to pass smog, You can buy a spacer for your downstream O2. It's cheating but pulling the rear O2 a little further back you can usually pass with no issue.

If you need to replace sensors check oxygengeek.com. When I replaced my upstream, I think it totalled out to about $42 shipped for a replacement Bosch sensor.

Update: New sparkies (BKR7E with 0.030 gap) didn't help, but logging different sensors on the emanage reveals that wiggling the TPS wire is causing output voltage variations. That could be it, but I noticed when I was driving and the engine stuttered that the emanage wasn't showing any unusual issues with the TPS, nor was the scangauge. The v-spikes might be so fast that the emanage can't detect it, but that's weird given how fast it monitors the wideband.

Walker 02 sensor on it's way too...

Ohm out your plug wires. Check your coil pack. They make little stutters when they start failing.

The Nology wires might make that a little difficult -they function like capacitors instead of normal wires. And in my experience, everytime I've had a bad wire, checking them with my multimeter has revealed nothing.

I've had the same coil pack for 140k, so that could be dying, but when I wiggled the tps and the car stumbled, that's just screaming bingo.

Originally posted by ez
I wiggled the tps and the car stumbled, that's just screaming bingo.

Wiggle it. Just a little bit.

Sounds like you're nailing that bastard down, Erik. Kudos.

I'm just glad Arizona can't dyno test a full time AWD vehicle yet. They don't connect to the ECU and just let it idle for 15 seconds or so. If nothing *looks* out of place, they pass.

It's getting to the point where the emissions test almost costs as much as the tags on the Galant. Lol.

Try just running some injector cleaner? high HC is unburned fuel, maybe you're injectors aren't misting properly and you're not quite getting a good burn at low heat/low rpm. fyi, runnin 6 heat spark plugs will help that a little bit, not much but a little. I'm having the same issue (all pass except 15 mph HC), but i think mine is my valves or something. But I changed my plugs fro 7's to 6's, put on a paper air filter (non-oiled), and it dropped it by like 10%.

What's weird, if I have turn the car on and test the voltage on the sensor, it goes up and down smoothly as I open and close the TB. I can plot it on the emanage and see that it makes a nice perfect trace from 0(closed) to 100%(open).

However, occasionally when I'm driving and come to a stop the TPS will hang around 30% (instead of dropping to around 0-2%) and the car will idle really crazy. Usually the crazy idle will go away in <30 seconds, or if I blip the throttle it will drop back down. My car has always done that since I dropped in the built motor. Never knew what was causing that. But I don't get how the TPS can spec out OK and then go schizo sometimes. I wonder if the internal mechanism is getting stuck. The wiring around the EGR pipe is ok. The connector to the tps seems on solid. Trying to figure this out before I buy an expensive new replacement (these things are costly!)