Wobbly on cold start

Recently my car's been kind of wobbly for about 30-60 seconds after a cold start--wobbly meaning it feels like the throttle is unsteady. The whole feeling reminds me of starting up my motorcycle cold and on choke, twist the throttle and nothing happens for a second and then it starts picking up. Any ideas as to what could be causing this? I would say a cold start valve or a fuel injector on its way out, but I'm still not very familiar with the mechanicals on this engine. Edit: It's a 2000 C2, btw, for whatever reason I can't find the spot to pop in a signature.

You sure your battery is topped up ok? I've seen this behavior when the battery is low, and the alternator is working hard to charge it A battery trickle charger took care of that issue. Other things that come to mind are cracked coil packs, which can cause rough idle when damp.

Already had a coil pack go out so this is not that--besides it's like this regardless of humidity/recent rain. So far as I can tell it's based solely on engine temp. Battery voltage is good, and this car is my DD so it's staying topped up, enough so that it shows no odd behavior after week long business trips.

Do the obvious first. Clean throttebody, check for vacuum leaks, make sure secondary air pump turns on and is free flowing and connections are good. (although you should get a CEL if not working). Most O2sensor problems will also generate a CEL. Reseat both the temperature sensor and MAF cable connections. Sometimes a CEL will not be generated if the secondary air valve partially but not fully opens. Check that tihis valve is open fully. It is controlled by an electric change over valve that feeds vacuum to the valve when activated. Valve will only be open when pump is running. You can test valve by feeding constant engine vacuum to it. Check the 2 vacuum lines on the changeover valve for proper connection.

Will give all that a shot when I get home, thanks muchly.

Dave!, You can not have a signature as a User. Only paying Members have access to the signature function. FYI, membership is $18 per year or $34 for two years.

Glad to see you back, Tim, and keeping things in line.

We have a cold front coming through and I've come down with something so I haven't had the chance to check what's up--I'll update this when I can get to it.

Haven't had much time to look at this anymore until now. Here's what the car's up to now: -Hesitation on cold start -Hesitation at very light throttle -Low idle for a few seconds on hot start, this afternoon it almost stalled out. Goes right back to 800 afterwards though. I would say I checked the secondary air injection but uh, nope, really don't know my way around the vacuum lines well enough to find it or mess with it. I've cleaned the throttle body before and sprayed, but didn't get with a q-tip, the MAF. Any ideas folks? Edit: Could fouled fuel injectors be the problem?

some ideas: check the ICV if its a 99, see renntech or search here for more, idle control valve Sounds like a MAF to me. Try disconnecting it (I'm not sure if these cars run without the MAF, my 2000 MB had a MAF go bad on a road trip and that's how I got it back home, no drama). If it runs without the MAF and it's smooth, then you've got your answer, replace the sensor (after testing the connector and wiring for continuity)

Just curious: when was the last time you changed the spark plugs?

No ICV but I can try running without the MAF. Supposedly at the 60k service performed the car's PO around 55k, though I was dubious about the dealer's documentation and I may as well pull a couple out this weekend to check. On the other hand the car is absolutely 100% fine on heavy acceleration so I wouldn't expect bad plugs to be the culprit.

Quotes source post: 6511004

Not sure if I saw mileage in the thread, but believe it or not - might be your cats going? I replaced both of mine under warranty in the past 6 months and I had a rough idle condition a few times prior to them going. If you're less than 75k miles and 8 years, change 'em quick! They should be covered under the emissions warranty. But you'd have to wait for them to code first, and the CEL will stay lit. I know this is a longshot - but just another piece of information that might help diagnose.

There is probably a fault code stored. Go to the stealer or Autozone and get the code read and short cut the whole affair. Mine was doing this and the reader said a bad lifter and it was. Pretty clever little computer!