New Cats

[Lnpr4eva]

First let me say hello to all.. I am new here.. Now I have a question.. I am working on building up my 95 GT 5.0 .. I recently put the Pypes High performance cats on my Stang after my stock went out .. My stang seems to be idling rough when coming to a stop.. It will shake crazy when Im slowing to a stop then stop just a fast as it started, no shaking in neutral just when coming to a stop and on start up, other wise it drives fine.. I didnt have this problem before the new cats were put on.. I was wondering if there is a connection? If not what should I be checking? I just did a complete tune up and oil change and had my fuel inj cleaned.. Im stumped.. Any help would be greatly appreciated. :

 

[Pennywise2]

Welcome to the Asylum.
If your idle is that bad than your Idle air control valve
probably needs replacing.If that is the case get a Motorcraft replacement.

 

[mo_dingo]

You might need to reset your computer.

Another thing is to clean your MAF & IAT sensors. They may be causing your problem. And reset the comp after you clean them, especially if they are really nasty.
Scott

 

[JJ95GTID]

You also might want to see if you have any codes coming up from the ECM. You may have a damaged O2 sensor. You can also check the O2 sensor connectors to see if they are on good.

 

[ProKiller]

i would check your o2 sensors first to make sure you didn't break them or something. how is the drive quality? usually if your o2s are bad, it won't feel right when you get on it, dogs out, etc. did you do the install? did you touch the sensor ends of the o2s?

by all means clean out your mass air sensor (MAS) and your incoming air temperature (IAS) and your incoming air controller (IAC).

 

[1TallMF]

+1 for the IAC, the port on the TB might just be carboned-up. But yeah, try to reset the computer first to see if it helps at all.