User1

After all I've been through with this car, I feel kinda retarded asking this question, but I have a hesitation right after a cold start and I don't know what it is. Only happens once in the day in the morning right after cold start and I put it in drive to leave. Put it in gear, step on the gas, it falls on it's face for a second, picks back up and runs fine the rest of the day. No codes. MAF is new/ish Hitachi, sensors are all good, CKP sensor is new, I'm kinda lost. It behaves like a cold electrical connection that isn't making contact until it warms up and expands, then it's fine.

It also seems to surge when I kick down a gear at speed. Like starving for fuel or something. Fuel pump is new/ish Walbro, no intake leaks/unmeasured intake air that I can see. My stuff is pretty clean. I've kept good care of it since the swap. 5k oil intervals, all kinds of regular maintenance, etc. Hood is often up, I haven't ignored this car.

Thanks all

uptownsamcv

what year car do you have?

User1

2003 with gen2 VQ swap

uptownsamcv

when you did the swap did you hard wire the throttle body or use an adapter?

User1

Interesting you ask about the throttle body wiring. I swapped in the beginning of 2019 and used the Nisformance pigtail for the throttle body. It gave me a lot of grief and I was constantly having to clear tb codes on the side of the road to be able to drive again. I ditched the Nisformance pigtail and hard-wired the throttle body and never had a problem again. This cold hesitation is the first time I've had an issue since. I think you might be going in the right direction with this. I'll look at the wiring and see if there's anything to see. I soldered the connections and do decent, proper work, so I'll be a bit surprised if it's my wiring.

uptownsamcv

what region do you live in?

have you tried throttle body cleaning?

a friend of mine has a 2018 civic and I recently had to do a throttle body cleaning on it. his throttle body was getting kinda laggy and a bit unresponsive. I had him hold the gas down as I sprayed carb cleaner into the valve cover breather tube that leads to the throttle body hose. he' isn't a car guy at all and was getting ready to trade it in thinking his transmission was going bad lol...

User1

I'm in Tampa. You can find my build threads in my history. I think I'll check tb connections and go from there. I'll keep you posted. I'm off Thursday. I'll be doing oil and filter then too.