Rough Idle... What Could Be My Problem?

[thepremier]

I am having some problems with my GN, but I can't seem to figure out what exactly is the problem. The car has a really rough idle, and at times the car will sputter for a couple of seconds when I take off from a stop position.

I have installed a new AC Delco Ignition Coil & Module, along with brand new MSD Plug Wires and spark plugs. TPS is set to .45, today I just installed a Fuel Pressure Gauge on the fuel rail, and it gave me a reading of 34 PSI at idle. Does this seem to be in the correct range at idle? The car has new 50# injectors from Precision Turbo along with a chip to match. The fuel filter is fairly new and doesn't appear to be going bad, the car does have the stock fuel pump, and I have the Walbro FP + Hotwire coming from Racetronix on Friday. I have a feeling that the stock pump is not getting the job done, but I cannot be sure until I install the new pump and hotwire.

I was also wondering if it could possibly be a problem with the Fuel Pressure Regulator. It is an Accufab regulator, but it previously installed by the owner when I bought the car 2 years ago. What are the signs of a bad Fuel Pressure Regulator, how would I go about diagnosing if it needs to be replaced?

All help would be greatly appreciated.

 

[Lee_Burough]

If I had your symptoms, I'd set the FP to 43-45PSI at idle -Your stock fuel pump should be good enough for a good idle for now.

What chip do you have? a modern chip is what you want to improve idle characteristics.

You need to replace any questionable vacuum tubing....A vacuum leak will cause your symptoms....BLMs will be high with a Vacuum leak.

When you set the TPS, you need to reset the IAC too....Then, check TPS and IAC within parameters before you quit....IAC can cause your sputtering from a stop.

 

[jake744]

Check and see if your egr valve is stuck open.