2004 Grand Prix Gt Intermittent Start issues

[mmertz3819]

I have a 2004 pontiac grand prix gt. In the morning I wake up and my car starts fine. However throughout the day when I get back in my car it dosn't always start unless I give the car gas.
Sometimes it will start up right away though and dont have to give it gas.

I know, sounds like a fuel pressure regulator well guess what? I replaced the Fuel pump (where the pressure regulator is located on my car) and still has not fixed the issue.

Today I will be changing out the spark plugs/boots and pac valve(very dirty)

I got a free diagnostic from a snap on machine from Amco. They said something about a MAP sensor needs to be replaced.

Does that have anything to do with my car not starting?

Any ideas if the spark plugs/pac valve/map sensor dont fix it?

[BNaylor]

Welcome to AF.

The '04 and up GP models under went a design change. To the drive by wire throttle body system and only a fuel pressure supply system with no return line back to the gas tank and fuel pump assembly. Also, the TPS design is different. To properly diagnose you may need to have it checked out with a GM Tech 2 scan tool at a GM dealership.

This is a common problem and one solution is to simply clean the throttle body. Here is the most recent post on a similar issue. Just do a search of the forum for many others.

Click here

Unless GM changed something a bad MAP sensor will not preclude the car from starting.

[rickisrad]

I agree with Bob on the Throttle body cleaning!! I had the same issue with my 04 and he suggested cleaning the throttle body and it cured it instantly. It takes all of 10 minutes to do

[mmertz3819]

Originally Posted by BNaylor

Welcome to AF.

The '04 and up GP models under went a design change. To the drive by wire throttle body system and only a fuel pressure supply system with no return line back to the gas tank and fuel pump assembly. Also, the TPS design is different. To properly diagnose you may need to have it checked out with a GM Tech 2 scan tool at a GM dealership.

This is a common problem and one solution is to simply clean the throttle body. Here is the most recent post on a similar issue. Just do a search of the forum for many others.

Click here

Unless GM changed something a bad MAP sensor will not preclude the car from starting.

Wow if this works I will be a very happy guy. I will be doing this tomorrow. Now when you clean the throttle body do you take it out, or can you just clean it when its connected?

[CrazyHorst]

FWIW, when ETC (electronic throttle control or "drive by wire") is used...the IAC motor is gone. The ETC is expected to control the idle by modulating the main big throttle blade.