Sorry if this is not the correct spot for this, I am a new member. I have a 1998 chevy blazer (approx 155K miles) which has hesitation after initially starting car. goes away in about 20 seconds and does not happen again (ie stopping at lights/stop signs etc) until car is turned off and restarted. Did spit out a P0174 code but has not occurred again (yet). Changed O2 sensor upstream of cat (bank 2), retightened upper and lower intake manifold bolts (had changed intake manifold gaskets about 3 months ago), tried vacuum testing with carb cleaner but did not see any change. After tightening bolts took for a short drive and after turning off car and restarting the transmission acted like it didn’t want to shift as well as the normal hesitation. (seemed to stay in 1st gear until I let off the gas, then drove normally). Just replaced fuel pump and fuel filter because bad fuel level sending unit. The hesitation and bad fuel gauge seemed to happen at about the same time but after doing the above, hesitation still present. Thanks for any help. Getting pretty frustrated.

 

I realize you replaced the fuel pump, but just because it's new, doesn't necessarily mean it's good. Follow the steps in this link, and post all 4 readings: https://blazerforum.com/forum/2nd-ge...eakdown-88305/