P0420 - '99 Miata -What Steps to Fix?

[dreiding]

I have a '99 Miata with 65K miles. Bought it used @ 32K in 2001. The Catayltic Converter was replaced just before the purchase. A week ago the P0420 code showed up. I replaced the plugs and wires. The code didn't reappear for another few days (30 miles). What's the next step? Isn't there a way to better pin-point the problem (Cat, O2 sensors, Coil ...).

Anyone in the Plano area you recommend that can help in understanding and fixing?

Thanks,
- Pat

[sammm]

I think the first step is to check out your O2 sensors.

If you want someone to work on it for you, send a PM to Rogue (on the forum here).

[cone-cerned]

Here is some info from OBD-Codes.com
Linkie

[jonlouie]

I have a '99 Miata with 65K miles. Bought it used @ 32K in 2001. The Catayltic Converter was replaced just before the purchase. A week ago the P0420 code showed up. I replaced the plugs and wires. The code didn't reappear for another few days (30 miles). What's the next step? Isn't there a way to better pin-point the problem (Cat, O2 sensors, Coil ...).

Anyone in the Plano area you recommend that can help in understanding and fixing?

Thanks,
- Pat

Miata tecnologies (on the web) Tom has been into miatas a long time. He put in a clutch,crankshaft positioning sensor, and front wheel hub along with some tune up stuff, at reasonable prices. Good Luck, Jonlouie

[trickyrix]

Rogue would be your best bet, although he's not exactly in the Plano area.

http://www.miatasolutions.com/

[riverracer]

Miata tecnologies (on the web) Tom has been into miatas a long time. He put in a clutch,crankshaft positioning sensor, and front wheel hub along with some tune up stuff, at reasonable prices. Good Luck, Jonlouie

Call Rogue at www.miatasolutions.com

[Bacon]

Call Rogue at www.miatasolutions.com

+1!! He's a good guy

[Monkey of Death]

Miata tecnologies (on the web) Tom has been into miatas a long time. He put in a clutch,crankshaft positioning sensor, and front wheel hub along with some tune up stuff, at reasonable prices. Good Luck, Jonlouie

Yeah, but what unsuspecting customer's car did he take the parts off of to put on yours? What parts from your car got swapped and you haven't noticed?

I'd rather have an epileptic, blind monkey hopped up on crack wielding a tire iron work on my Miata than ever let Miata Technologies touch it again.

Call Rogue.
Or a spastic, blind, crack monkey.
But Rogue does better work

[XM_Rocks]

I just had this same issue:

http://forums.dfwmiata.com/showthread.php?t=11027

Do you notice your car running rich?

Here is probably the fix for you.

$47 in parts and about 2 hours of work.

http://forums.dfwmiata.com/showthread.php?t=11494

[MadMonkey]

+1 for Rogue at Miata Solutions. My car is actually at his shop right now