Question : 3.4l starting issues.

[ad1harvey]

Alright so I am new here and have been trying to do some research to see if anyone can help me out here because I am at a loss so far. I have a 95 GTP and when starting in the mourning starts fine a good majority of the time but when starting any other time after that I have got to pedal the start as if it were carburated. Then when I do get it started after that I have got to crank it up to 1500 rpms for a while until it clears up. To go along with that issue the car idles rough until I drive it for a while then it clears up. Now I have already changed the idle air control and the intake manifold gaskets as well as the fuel pump and am having no luck. Any suggestions?

[geoffinbc]

Did you change the fuel filter? Do you have a way to check fuel pressure?

[Schurkey]

Scan tool --> what is the coolant temperature vs. ambient temperature when the vehicle has been sitting for hours.

(They better be the same temperature)

What is the coolant temperature when the engine has been running?

(better show the engine warming up properly; and being held at/near the thermostat rating.)

Coolant temperature showing as overly cold compared to reality will result in a very rich mixture; and that's about what your symptoms are.

[ad1harvey]

Temp & Pressure.

I changed the fuel filter the same time I changed the fuel pump. I do not have a way to check the pressure currently unless advance auto rents that tool out which I would have to check on. When I can get the engine to stay at idle for some time it will get up to about 210 before the fan kicks on along with the pump. Now as soon as I get to driving the temperature indicates steady at 150 unless I am in stop and go which in that case goes up to 210 and shoots back down from there. Now from there I am not to sure but would that make a difference on the vehicle being hard to start or just make it idle as crazy as it has.

[Schurkey]

Dash gauge may not use the same sensor that the computer uses.

The computer might think the engine is cold even though the dash gauge is telling you it's fully warmed up.

Thus the recommendation to check it with a scan tool.

[ad1harvey]

I fully understood what you meant with the scan tool. I currently do not have one so went ahead with the gauge reading. I do know just from standing behind the car that it is running rich. It has been for some time. Changed the coolant temperature sensor about 9 months ago and when I did that this whole issue just got worse so have been trying to figure it out ever since.

[RedZMonte]

what sensor did you run? i broke the one for gauge and i had 3 from the parts store that did not work (pegged hot after a few min) have verified it was the correct one listed for my car, got a oem one from amazon and wow everything works. could be a simmilar issue... especially if it got worse after you replaced it.

have you replaced anything else? O2 sensor, Injector O-rings, ect?

[TurboGTU]

Easy one, after it acts up, shut it off. pull the hose off the fuel pressure regulator. If there's fuel in the port and in the vacume hose, theres your problem, a leaking fuel pressure regulator.