The 1st time in the morning I start my stang it dies and the 2nd it always starts fine.I recently replaced the ACT, ECT, cap, rotor, coil, wires, plugs,fuel filter,IAC, and fuel pump.The only codes i get are 34 and 91.I will be replacing the EGR valve and position sensor as well as both 02's.So I think that will take care of the codes but I dont think it has anything to do with the cold start.Am I wrong?I dont know what else it could be.Any advice?

 

did you verify your base timing, tps setting and base idle? clean MAF too. did you check for vac leaks? make sure your o2's are seated all the way in the bung and you dont have an exaust before the o2.

 

I just cleaned the MAF w/ MAF cleaner.I also just tightened my headers and both 02's are fully seated and I cant find any vac leaks.Just checked timing and its set @ 11*.I dont have the right tool to check the TPS.Wouldnt it through a code if the TPS setting was incorrect?

 

yes it would

do you have an adjustable FPR? or a gauge on your fuel system anywhere to show fp?

 

no.thats what i was thinking about.does the pressure change only on 1st start?every other time through out the day it starts fine

 

no, but if you have a crack in your return line or if your fuel pump check valve is damaged it wont build pressure right away. i had the same problem with my car. hook a guage up to it and see what the pressure is on first start mine was around 10-15psi until i tried a few times and then it bumped up to 30psi ish

 

Here is a simple thing you can do to find out if f/p is bleeding down. Before you make the first start, cycle the key on then off twice making sure the pump is energizing. On the third try start the car. If it starts w/o dieing, something is happening to the f/p as it sits. If it still dies, you'll have to look elsewhere for the cause.

 

yea thats what i had to do when my check valve was bad in my fp.

also i think it was MJR said it could be the return line could be leaking and losing the pressure.

 

perform a FP test as POR50SC stated and check for bleed down

 

I think if it was losing pressure it would start harder but once it was running it would continue to run because the pump would be running.