nhyrum

My dad's 98 gt dies whenever you don't let it gently come down to an idle. In other words, 99% of the time it instantly dies at idle. Took it down to my friend at the part store and hooked a simple scan tool and got only one dtc code, p0171 with no p0174 code. So it has a bank one too lean code. I didn't notice any bad vacuum leak sounds. I got it to idle very rough long enough for me to look under the hood for vacuum leaks.

What I think may be eliminated:
Maf sensor, it's only the one side that's lean
Plugged fuel filter(again, it's only the one side)

What I think it could be:
-Intake manifold leak on the bank one side(passenger side I believe)
-Plugged injectors
-vacuum leak maybe somewhere I didn't get to

So I'm wondering what you boys think and how I could narrow it down

Thanks in advance!!

nhyrum

and the theft light flashes almost like it has a wire loose, with no noticible pattern

TXMach

I don't know if you looked at this already but there's some causes and solutions listed.

http://www.obd-codes.com/p0171

tadpole1969

first thing get some starter fluid spray small amounts around vacum hoses and intake and throttle body if it increase's the idle then you found your problem most likely a vacum leak

TXMach

+1 on this. Worked for me.

nhyrum

thanks guys.

First of all, yes i have looked at that site.

Next, I think I will try spraying around with ether. Seems to be a good way to tell if it is indeed a vacuum leak.

Me and my dad tend to lean towards the injectors being bad. They have not been rebuild in the 9 years we have owned the car, and the intake was replaced a few years ago, i do not think the seal has gone bad already... unless the hot-rodding around... done by... i dunno...(my dad is now past his mid-life crisis)... has tweaked things.

Its a fun lil car and i want to get her fixed!

P.S. If we do get new injetors, how big is TOO big on a stock set up... 36 lb? 50 lb??95lb???? (ok im pretty sure 95LB/hr (1000cc/min) injectors will be WAY TOO HUGE)

WJL

Being it's a 1998 you more than likely have ignition wires(which will occasionally arc), just a word to the wise "Have a FIRE EXTINGUISHER near by"

TXMach

For a stock set up you should go no bigger than 21lb/hr. It's all about duty cycle; i.e. how hard the injectors have to work to provide the necessary fuel. If you go any bigger than that on a stock set up it's gonna be wayyyyyy too rich when you floor it.

nhyrum

drove it till a light came on, both sides running lean. sprayed ether around the intake with no change in idle pattern. took off the MAS and sprayed it woth special mass air flow sensor cleaner and sprayed a crap ton of chemtool carb cleaner down the TB with black gunk flowing back down back at me(the engine was off so it wasnt sucked in) let it sit for quite a while, started it up and continued spraying more. SUCCESS!!! idles good and purrs like a kitten.

Thanks all for the help!