very hard start after sitting a day or overnight
 

I cant seem to figure this one out...it did this before I replaced the fuel pump a few weeks ago (delphi oem pump). If the truck sits overnight or I let it sit a full day...it starts very rough...like holding the key forward and starter dragging. I just replaced the IAC because it kept jumping rpms at start up and that seemed to fixed the rpm problem

What should I check. ..battery seems fine and is just a year old....altenator is 2 years old but a remand and I just cleaned the throttle body when the iac was put in.

Also the truck starts perfectly fine after its been started in the last 6 or minus hours


Any suggestions? Thank you!

How old are the plugs, plug wires, distributor cap, rotor? How many miles on Blazer and is it the original distributor? Is the coolant temp sensor connected and working?

Plug and wires and cap and rotot were done 30k ago....I have 165k on it and im not 100% sure if its the originial distributor or not...Ill have to look at the bills when I got the tune up and see if that was replaced. And yes the coolant temp sensor is connected and working

also going to take a friends advice and tomorrow morning cycle the key 2-3 times then see if that helps, if not I wanna make sure its not a battery issue, so I will get that tested from where I bought it

A fuel pressure and leak down test should be done. Sounds like you have a leak in the system draining off pressure.

what are the proper procedures for the pressure and leakdown test, im kinda a noob when it comes to this, any videos showing how to do this properly?

will have to see if advanced auto will loan it for me, and ill get the battery tested at the same time

did the fuel line need to be bled after the fuel pump was installed?

im going to have to buy one...NO one rents them (pepgirls advanced or autozone.) any brands you guys recommend?

UPDATE: took my friends advice and did the easy free thing before i spent money on a pressure tester, got my battery tested. it failed in cranking amps, the guy was suprised i was able to start my vehicle with what it registered. got a brand new one under warranty. gonna see if this was the reason why it was starting hard