Starting this thread over because I don't think it's a fuel pressure issue. It always starts great on the first start of the day. When I get in after being at work all day, it cranks and almost starts but won't quite catch and run. It's still at work as I writhe this thread. I've checked fuel pressure and it was good. Fuel regulator test was good. I sprayed ether in the throttle body when cranking and no difference. I went through other checks in my previous thread titled '00 S10 2.2 fuel press check? The truck sat in the garage for 2 weeks and started every time whether it was warm or not. I needed it today so I trusted it to take me to work. The wife has come to pick me up twice now in 2 weeks. So far I've replaced both O2 sensors. I had a SES light for the aft sensor that's gone now since replacing it. The engine was replaced 3K ago and runs great when it runs. The entire exhaust was rusted out so I ran a straight pipe W/O the CAT to a muffler. It has a header and CAI. I think its a sensor but I'm not sure how to check them. MAP, MAF look good and are clean. Can I ohm them out? What should the values be? Will the TPS cause this? Or the water temp sensor? Is there a crank position sensor that could be throwing off my timing? The wife is taking me to work at 5:30 AM (she's happy) and it will start right up. She'll bring ut home and park it again so I'll check it when I get home. If I catch it not starting at home I can check spark.