I made a post 2 weeks ago not a single response ... I am having a problem with my 99 gs starting after warm first start of the day is fine short trips are the problem I already replaced fuel pump and fuel pump ecu both from junk yard please anything will help can't find any information on net about this problem

 

Check your intake hose. I just had this same problem and found that the hose after the MAF sensor had broken off. This would cause your car to run lean. Temp wouldnt regulate this, its just a guess, but I would assume once the car sits overnight, maybe the ecu resets and starts from fresh in the morning, then as you drive it during the day, the extra air coming in after the MAF is creating, as I said, a lean code and the ecu just shuts off to prevent further damage.

 

Thanks for replying but the hose is good... The car runs fine other wise as long as it stays on once u try to restart if it hasn't been sitting for a while it takes a long time to start just cranking until it finally catches



While checking the hose I saw this sensor looks like it's covered in oil could this be the problem

 

Is it dropping any codes? Not sure if this would cause your problem but it needs to be attended to. Probably an OCV, VVT-i pulley or cam seal leak.