removed cats, now problems

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Feb 22, 2011 | 07:53 PM

High_Angle

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Staging Lane

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removed cats, now problems

My 2002 WS6 recently got qtp longtube headers, no cats, true 3 inch dual exhaust exiting at factory points, new plugs at .50, new gm gaskets and im having problems.

first was the SES light, i expected that but its been stuttering in all rpms, wont accelerate properly. its an automatic and its backfiring quite a bit.

its drives normally when its cold but when it warms up, the problems begin. I live at 4000 ft, use 91 octane. i removed the PCM to send to TSP so they can do a tune for me.

im pretty sure its just waay to rich because of a combination of no cats, altitude and 91 octane. right?

Feb 22, 2011 | 07:55 PM

TImmy_Jones

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I have been there before, CHECK FOR VAC LEAKS!!! Scan that code....loose AIR or EGR fitting and you will have a vac leak. Does the car backfire at all? Could always be a bad maf. Scan the code and get back to us.

Car will run fine with bolt ons and no tune, it just wont be OPTIMAL.

Feb 22, 2011 | 08:04 PM

High_Angle

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Staging Lane

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the car does backfire, seems like more every day. i also removed the air pump and hoses.

Feb 23, 2011 | 08:45 AM

TImmy_Jones

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Screams vac leak to me. Two big things to check: make sure your plug wires are on the plugs and NOT melted by the headers, inspect each one of them! If that looks ok, I would buy some carb cleaner and spray around the engine bay, if the idle hiccups and raises a bit you found your leak. I bet you have a 'lean on bank x' code or EGR code. Please check the easy stuff, I thought my car had a busted MAF, ended up being a super easy vac leak.

Feb 23, 2011 | 04:50 PM

35th camaro

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did you at lease put the 2 front O2 sensor back one the headers, the rear one's are not as important they are only there to monitor the effeciency of the cats, they do not affect drivability

Feb 23, 2011 | 05:04 PM

2xLS1

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From: Warr Acres, OK

My bet is you probably have 1 or more cracked plugs. I see it all the time after header installs.

Feb 23, 2011 | 05:41 PM

Bird

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From: Spring, Tx.

Quote:

Originally Posted by 35th camaro

did you at lease put the 2 front O2 sensor back one the headers, the rear one's are not as important they are only there to monitor the effeciency of the cats, they do not affect drivability

+1

If it runs decent in open loop (cold) and then turns to crap in closed loop (warm), then I'd look real hard at the O2 sensors / harnesses.

Bird