the past couple days, it's been getting cold around here (down to the low 60's) and when i start my car, it doesn't go more than 3K or so before the car starts to buck. i can hear the primary spooling up right before the car starts to shake, and it seems to drive fine after putting around for a good 5-10 minutes at low speeds. i'm not an expert but it feels almost like fuel is being cut off. has anyone else had a situation similar to this? is it because of the cold start?

 

also forgot to mention that when i try to push it past 3K and it starts to buck, there's backfire when i let off the throttle too. my mods are an intake, downpipe, exhaust with stock ecu.

 

Do you have the coolant line still running through the throttle body?

 

i have no idea..how can i check this?

 

anyone? it's starting to worry me and the only rotary shop near me is closed on weekends.

 

look at your throttlebody and see if there are coolant lines running to it like Mahjik said. does it go past 3k after its warmed up?

 

I have the same problem, i think its sensor related though.

If i dont warm up the car to about 110-115F, the car would buck in low rpms.

There are even times where the car would be warmed up and i would park at the store, come out like 10 minutes later and the car would buck in the initial 5 minutes, even though the car is at operating temp. But then it clears out completely after the initial 5 minutes.

Im guessing its probably the coolant thermosensor? Maybe its telling the ECU to dump fuel unknowing the car is technically at operating temp and causing the car to buck because of running rich.

I dont know.

 

also check your double throttle, if its not working correctly it could be staying closed. and, correct me if im wrong, if the double throttles closed the computer would think its open, and inject more fuel, but since its stuck shut its preventing the air from getting to the chamber which would make it run rich and lead to backfiring