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why does my car idle so rough when i first start it?

14K views 13 replies 10 participants last post by  grbrgrnzx5 
#1 ·
every morning when i go out to my car and start it to let it warm up a minute it sounds like its got huge cams in it or like its misfiring. just a minute or 2 later and it sounds fine. i dont get it :dunno:

pretty much stock 02 with 28k on it
 
#4 ·
Yes, but I'd have to say the SVT is notorious for it. You know what helped my morning starts a little? Doing the Big 3 ground upgrade. Allows your starter system to get full juice. Maybe I'm just telling myself that, but I could swear it fires up better.
 
#6 ·
TJs98GT said:
it sounds like its got huge cams in it
Mostly because it does have large cams compared to a typical 4 cylinder of similar displacement. Even though it has the variable cam timing to help out, the lobes themselves are still the same size. If the cold start idle speed was a little faster, you wouldn't hear it as much.
 
#7 ·
Well when the car starts up first thing in the morning the cat is cold. The factory tune is designed to try to get the cat up to opperating temps as quick as it can. So that is why I think the car sounds like crap when starting up in the morning.
 
#11 ·
i was debating doing the big 3 upgrade to see if it helps but just havent had the time or money to allocate to this car right now.

the tune on it is the newer version, not the stock 02 one. i forget the code used.

sounds like they all do it though so ill just deal with it
 
#13 ·
grbrgrnzx5 said:
Never heard the term "big 3 upgrade" before. What does it mean?

Not to thread jack...
The Big 3 grounds/connections that suck large...you know. They are: negative battery terminal to chassis, alternator to positive battery, and engine to chassis. Just do a search of FocalJet and you should find pictures of them. I would say my dash lights flicker a little less after doing them.
 
#14 ·
Okay, thanks. I installed a ground kit on my older Zetec Focus. Not sure if it helped me make more power or improve any reliability or electrical system stability, but it did quiet some of the amp whine that I got over my aftermarket stereo.
 
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