Thread: car runs soooo much better before its warmed up.. why?

Sooo here's a fun one, I got my nx2000.. Short ram intake, regrounded maf, header and exhaust.. I've checked the tps, fairly new o2 sensor(maybe bad?), checked for vaccum leaks and nothing.. So when I first start my car after its been sitting for a good while or over night it'll start off very very strong for the first 5-15minutes.. Then after, blah.. It feels like I'm pulling a boat, the car will rev and everything but it'll accelerate sooo slow. Its really starting to piss me off so any help would be greatly appricated. Thanks guys..

Its an internal cumbustion engine and its hot outside lol. Less heat...more power. You didnt complain of stumbling or anything so its prob just you getting used to the Highport DE.. Your G20 has the same motor sort of but the tq comes in lower where you want it. Instead of you having to rev it.

I understand that you will obviously loose some power since the engine bay will get hotter but the loss is dramatic it isn't something little, but I have had the nx for years now the g20 for a lil over a year plus the g20 is automatic I rarely get on it.. But like I said, it doesn't really stumble I mean it'll drive fine as long as I don't expect it to haul ass lol.. The only thing that seems to make any difference was when I adjusted my tps it gave me some power back but not all of it..

Check your coolant temp sensor. It could be bad, if u have nissan datascan do a sensor check.

That's actually the second time I've heard that lol, Ill look at that next!.. Any way to test it without datascan??

I think its Coolant Temp Sensor too. Doesn't that threw a code thou..???

That's actually why I didn't check it the first time it was suggested to me, cuz I thought it threw a code too..

It might not throw a code unless it's just missing lol. Check the fsm you can prob check the ohms on it to see if it's still good.

catalytic converter could be going bad.

O2 sensor can also cause this. The car is fine until it gets to closed loop mode (warmed up). This means one of the sensors used for closed loop mode is fucked. Coolant temp sensor is common. O2 sensor is next.