Hesitation/slipping on acceleration while engine cold

4banger Auto....Searched the forums and did not see anything. This is hard to describe and once again the techs don't think anything is wrong but, when the engine is still cold and I am leaving the neighborhood I get a slight slip or hesitation in the engine while accelerating.

It is very slight but enough to feel the truck surge forward three or four times and you can hear the engine kick in also. It would be similar to completely letting off the gas and quickly getting back on it but there is no way my foot can move that fast. After the engine warms up the problem is gone and as you can imagine the problem is exaggerated when it is extremely cold outside. One thought was a bad spark plug or wire but then why would the issue correct itself when the engine warms up? Any thoughts or has anyone experienced something similar?

 

first I've heard of this with a 4banger... but is very common on the 6banger autos. probably would see misfires in live OBD data too... personally I think they designed these to run so far on the edge that they intentionally misfire. kind of like a drunk person driving with double vision slowly bumping into curbs to make sure they stay on the road... sounds like the craziest theory ever, but you have to throw like 65,000 (not exaggerating) misfires before any codes will pop on these.

 

Could it be the engine knocking when it's cold?

 

I just had my first service today at Toyota. I have a similar issue with the RPM shooting up when the engine is colder. The tech was very helpful and explained a lot, basically what he explained is "thats how these guys run now a days. Once its warm it goes away correct?". Its true it does go away after about 10 minutes of running. It's a big frustrating.

 

65000?

Nah it isn't a loud "knocking" noise.

 

Man these things are all over the map. My RPM's start to drop but again, its very quick so and its almost like the engine is completely cutting out but starts up right where it left off. Kinda like starting a lawn mower and you can hear it cutting in and out as it warms up till it eventually runs real smooth.

 

Defroster on? Air conditioner helps with defrost and bumps rpm when it kicks in. Might happen if you are just idling down the road, once on the gas it shouldn't lurch.

 

Sounds to me like your auto tranny is low on fluid....do you have an auto..?
If you are low...it will slip when cold and then when warms the fluid expands enough to make it run better...
If you have the auto...First thing to do is make sure it's full to the proper level.... A physical check must be done...NOT a computer check by the Tech....