Before the car is warm, usually when it is cold out and I just start driving I'm getting serious bucking in 1st-3rd gears.

For example: Release clutch pedal, then change gears to second and kind of coast with minimal throttle the car bucks like hell until I push the clutch pedal back in. When it is warm, there are no symptoms except the typical bucking. BTW, I have an updated MAF.

 

That's typically the Fuel Cut problem. I'm surprised you don't see those symptoms in warm weather; you probably should. There's a TSB you can have done at a dealership (supposedly ~1/2 hour labor?) to reprogram the ECU to eliminate that below 1800 RPM I believe. I haven't had it done yet.

 

Actually, on second thought, I find that this "bucking" is a little worse when the engine is cold than when it's warmed up. Even in 9F weather, if my engine is warmed up, it feels just like it does (bucking-wise) at 90F outside.
I have the original MAF, for comparison.

 

I have and it still bucks, just not as bad.

However, now with the fuel-cut TSB during cold weather it chugs/dogs until you hit about 2500-2600 and then takes off.

Once warm, no problem.

 

Did they reflash the ECU when I had the MAF replaced nearly a year ago? Or did they just reset it do you think?

 

Could be either...should say on the receipt or they can look it up for you if you call the dealer.

 

Thanks, Ice, I'll check it out. No sense in spending $50 if I won't notice a difference.

 

Oh, you'll notice a difference, I'm just not sure it's better, just different.

 

I still have the fuel cut issue, no tsb was performed. I heard that most cars have shown a 3-4hp loss after the ecu is reflashed. any dealer can see if you have had the tsb performed, either through their records, or they can plug in a consult II and check to see if your ecm PN is current. I asked the previous owner of my car why he didn't have it done, as i owned it post-warranty, and he said he heard the same thing from the tech at the dealer, and decided against it. I haven't any dynos to proove it or disproove this, if someone does, please shed some light, thanks

 

While this is a little different, my daughter's Cherokee did the same thing. Our mechanic said it was a dirty intake manifold. He cleand it out and it ran fine since. Don't know if would be the same for a Max.