Backfiring and bouncing at 3k BUT ONLY ON A COLD START

[Supra-Man18]

Every morning i start up n head to work the first 2 minutes of driving the car sputters around 2500rpm's and backfires badly.. It feels like the car wants to go but its being held back.. like the ecu pulling timing or something.. But after about 5 mins of driving.. It all clears up n she runs Perfect... Anyone have an idea on what this can be ?

 

[nthilavan]

i have a similar issues. i found if i let the car warm up about 10 mins it works good.. but i have alarm with remote start that make it easier.

 

[ae86ma70]

Idle air control valve possibly? Remove the two 12mm bolts and check the screen underneath the IAC valve. Pull it out and blast it with some Air Intake/Carburetor cleaner and reinstall. Hope this helps.

 

[mk3tattoos]

You should never let your car warm up for 10min......start car, wait 10sec, then drive.
You are doing more bad than good by letting it just idle for 10min.

 

[Supra-Man18]

Calm easy driving is a much better warm up process on your motor... And then you can unleash hell when its all warmed up !

 

[Chambers]

I have another case similar, my 1UZ. On cold starts, and it’s been extremely bad lately from being seasonally cold, it sounds and shows (on the tach) like its breaking up like one cylinder is not getting enough fuel, spark, or compression. If I try to drive it before the "popping" subsides (from warming up) it’s almost unbearable to drive it. If I let it warm up, I can pull usually to 4500-5000 rpms before I get any sign of breaking up. If I do not let it warm up, and start driving after reaching operating temps I can only pull 3000 rpms before it breaks up.

At first I thought it was power to the fuel injectors/ ignition coils. I made sure they both had ample power and the "popping" persisted. I recently replaced the fuel injectors, thinking maybe one was bad and the “popping” still were there. So that leaves, compression, I have not done a proper compression test but I have turned the crank over by hand. Literally I can take my two hands and turn the crank, vs. my spare engine which requires a rather large wrench to get it moving, both being cold when turned.

Maybe you need to do a compression test on your engine to see if there are any issues.

 

[destrux]

I'd test your sensors when the car is cold. It sounds like one of them has a problem that only exists when it's cold. You could have good comp, powerful spark, and enough fuel... but still have a problem if the ecu is sending incorrect signals to them because of a bad input sensor. TPS, cam sensor, map sensor....etc....