No check engine light is on and the trucks done this for the last 8 years it has 350k on it so. But if I go to start the vehicle cold it will start with a bit of a misfire or a rough initial start and shake for a second..... after that if I let it idle for just 2 minutes and I shut it off and I start it up than its nice and smooth however once the vehicle gets warmed up and I shut it off and crank it up it gives me that 1 second nice shake on start? IAC? LOWER INTAKE? I did the isolator bolts. Just did the fuel pump which even before the fuel pumpnwas replaced it still gave the rough initial start. Fuel filter and air filter are always done on time sooner than later actually.....I've tried cleaning the iac and MAF and no luck... I've noticed I have 1 broken exhausted manifold studd that's about it..... never smoked the engine however.... no vacuum.hoses have holes in them....I possibly was thinking the butterfly valves? I did replace that stupid price of white plastic where u have to stand on ur head I did that 4 years ago but really who knows if that's the issue.......its just annoying start. And the rims go up to about 1600 on cold start and a bit lower on a warm start up which leads me.to believe lower intake.manifild? Not burning any coolant however thankfully.... maybe its just old.... its got lots of.kms.and I got it at 298 000kms so...... maybe its its just a near dead cylinder or the iac? Air temp sensor who knows.... no check engine light tho.... and the check engine light does work obviously checked in run position it illuminates and on it goes out like suppose to so? Lol

 

Any codes?