SparkyJJO

iTrader: (11)

My car has always done this ever since it got cold. When I first start the car, it idles higher (normal). When it is colder out though (anywhere below 35 or so), if I tap the gas pedal, even just lightly, the engine bogs, then revs up above the normal cold idle by a few hundred RPM then eases back down. The colder it is, the worse it is generally. Let it sit and idle for about a minute and it is OK after that mostly, just a little touchy. Come on, even my old 93 taurus didn't do that.

Thing I wonder is my MPG is down too. Now I expect it to be lower in the winter than the summer (idling the car more to warm it up, winter gas formulation sucks) but I went from 27 highway with some city mixed in to around a consistent 22-24. There is a little more city mixed in now than previously due to driving to work each day now but the majority of the drive is still on the highway.

Exhaust smells a bit rich too, at least compared to my old car. Maybe it is just me though, I don't know. I don't spend time sniffing my tailpipe heavily

Could it be MAF is dirty perhaps? Something else, like O2 sensor? Or is it just my car is picky about the cold? Could these things even be related? I have no SES light (yes it does work, it sure let me know things were wrong when the lifters went bad!).

Since I got the car in september 07 I have seafoamed, changed fuel filter, plugs and wires (which were original ) checked the air filter (is fairly fresh), and now my intake is fully cleaned out since I had to get the lifters replaced the shop cleaned it up for me. Tires are new in October, pressure is normal.

SparkyJJO

iTrader: (11)

anyone?

xBROKEx

iTrader: (7)

have you checked to see if its throwing a code

Spink

iTrader: (1)

Could be a dirty MAF, that's definitely where I'd start. Get some MAF cleaner for $5.00 and spray it really good. Don't touch the sensor though, just spray it. If you didn't clean the IAC valve that would be another good thing to clean. It wouldn't be an 02 because those don't give feedback until the engine is up to temp.

Could be a vacuum leak as well. Possibly a hose is cracking and it only leaks when the rubber is cold and less pliable. Spray some intake cleaner around the various hoses and if your idle changes you've found your leak. It evaporates right away so don't worry about it making a mess. Just avoid completely soaking any electrical components.

If you have an oiled K&N filter that may be getting oil on your maf and then as the maf heats up it burns most of it off.

You might also want to read this thread.

https://ls1tech.com/forums/general-maintenance-repairs/838670-cold-start-morning.html

SparkyJJO

iTrader: (11)

Thanks for the input guys. I wondered about the MAF as that is one thing I haven't touched yet. I read that thread and I know it isn't my intake manifold isn't tight because it did this before and after I got the lifters replaced so the intake had been removed and put back on.

xBROKEx, if it was throwing a code, wouldn't the SES light be on? Next weekend I'll see about going to advance auto and getting the codes checked. Got the flu right now so I'm not going anywhere for a bit

Spink

iTrader: (1)

My maf was dirty and when I cleaned it there was a big difference in how the car ran. I clean mine every oil change now. It's one of those things that will gradually sap power as it gets dirty and by the time you notice, or get a code, you've already drove months with the car underperforming.

SparkyJJO

iTrader: (11)

Mine being a 3800 V6 isn't going to be much different as far as the MAF goes is it?

Spink

iTrader: (1)

No, it still gets dirty and affects the car the same way. Just spray it real good with MAF cleaner and be careful not to touch the wires in there. They're very sensitive and they'll break easily.