Tach jumps

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Dec 27, 2010 | 07:51 AM

Slammed98silvercoupe

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Joined: Sep 2010

Posts: 118

Tach jumps

Yesterday I'm in 5th gear and gave it gas and car ran SMOOTH, but noticed that the tach was jumping, only cel is p0420-has had this for months & Im sure its not the issue. I then noticed that it did this in almost any gear and did this around 4k rpm. Any ideas on this please.

Dec 27, 2010 | 11:38 AM

PunisherInOKC

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Joined: Jan 2008

Posts: 1,059

From: Oklahoma City

Guessing after market tach? Check your wiring.

Dec 27, 2010 | 02:11 PM

Slammed98silvercoupe

Thread Starter

HCF Member

Joined: Sep 2010

Posts: 118

no, factory...all wires seem ok

Dec 27, 2010 | 06:32 PM

DaOne

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Joined: Sep 2009

Posts: 1,224

From: Sparks Nv.

I would fix the Check Engine light first...
P0420 - Catalyst System Efficiency Below Threshold
could be an exhaust leak..damaged O2 sensor...plugged catalytic converter...