1999 Sierra Stalled While Driving

xzz0195 · July 4, 2010

Yesterday my son was driving the truck (about 50 miles or so) and it just died. I went to help him, truck started right up!!! But only went 100 feet before dying.

Plugged in OBD2 and there were no codes... Am thinking this has something to do with Fuel or Ignition. Suspect Fuel because one time long ago I had a vehicle that would stall frequently, but run well otherwise. It turned out to be dirt in the gas tank clogging the fuel filter. On that vehicle we dropped the tank and cleaned it, no problems after that...

Also, this truck has the infamous sticking throttle problem which a good cleaning of the throttle body did not fix..

One other thing, for past year, fuel gauge bounces showing no fuel when it is full. If I jerk the steering wheel when stopped, fuel gauge responds.

Thoughts?

bossier62guy · July 4, 2010

Yesterday my son was driving the truck (about 50 miles or so) and it just died. I went to help him, truck started right up!!! But only went 100 feet before dying.

Plugged in OBD2 and there were no codes... Am thinking this has something to do with Fuel or Ignition. Suspect Fuel because one time long ago I had a vehicle that would stall frequently, but run well otherwise. It turned out to be dirt in the gas tank clogging the fuel filter. On that vehicle we dropped the tank and cleaned it, no problems after that...

Also, this truck has the infamous sticking throttle problem which a good cleaning of the throttle body did not fix..

One other thing, for past year, fuel gauge bounces showing no fuel when it is full. If I jerk the steering wheel when stopped, fuel gauge responds.

Thoughts?

My thoughts are that your fuel pump has finally given out. Check the fuel pressure to be sure. Secondly, if cleaning the throttle body did not remedy the sticking accelerator pedal then clean it again. Your third issue should be taken care of by the fuel pump replacement (if it is indeeed toast).

oldmann · July 5, 2010

Gotta be a pesky fuel pump. I've changed 2.

98 Z71 SLT · July 5, 2010

Definitely fuel pump...all the classic symptoms...

xzz0195 · July 6, 2010

Definitely fuel pump...all the classic symptoms...

Thanks for all the replies. I'll check into a new fuel pump. Side note: Today I removed the throttle body... To take a closer look at the sticking accelerator issue. Turns out the unit was completely clean but still sticking when accelerator was released quickly, so I removed the the two T10 bolts which were holding in the "flapper". As I looked closely at the edges of that piece of aluminum, I could see where it was actually rubbing against the throttle body. So I took some 600 grit sandpaper and gently sanded the marks until there were none, put the unit back in a will test tomorrow (starting engine), but the accelerator pedal does not stick now even when releasing gas pedal hard... I'll give it full test tomorrow and post back.

I replaced the fuel sensor on the fuel rail today, had to use C-Clamp to hold it in due to the internal o-ring needing to be compressed... Hope that was right thing to do. It was only way to get clamp on. Those units have two orings and outer and inner ring, the inner ring compresses against the vacum side of things.

Willshire · July 6, 2010

I have the fuel gauge issue on my 2000 Sierra. I believe the electrical contacts at the full point of the sender are toast. But my pump still seams to work fine. I keep a half tank of gas in it at all times to maintain the cooling of the pump. I am sure the pump is getting on in years and I'll have to put her down soon but, until it leaves me on the side of the road, drive on. I too have the sticky throttle plate, I'll have to look into sanding it a little.

ColoradoSkiCountry · July 6, 2010

Replace the fuel sending unit module, that'll take care of the crappy working gas gauge and fuel pump at the same time.

xzz0195 · July 7, 2010

OK update:

1) Sticky Gas Pedal Problem can definitely be fixed by unscrewing the two T10 bolts from Throttle body plate, remove throttle body plate, very closely examine for scratches by examining the edges of plate. Lightly sand with 600 grit sandpaper until no scratches are left. (Forget the GM bulletin on plugging hole, checking Throttle Position Sensor for .69 volts), the problem is mechanical not electrical. Root Cause is most likely warped aluminum throttle body for my 11 year old GMC.

2) If you replace the fuel pressure sensor on the fuel rail (driver's side) note that it will be very tough to get into place. There are two o-rings on the unit, the small one is for the vacuum, the larger for the gas. You will have to use a c-clamp to compress the inner smaller o-ring enough to get the clamp to fit correctly, once you do that it's a breeze.

3) The fuel filter is located just back from the driver's seat. It's tucked into the steel beam (main frame beam) out of view, you have to jack vehicle up to get a creeper under there. You will need two wrenches, a 7/8" or pair of Vise grip to hold the larger nut on the filter itself, while you use a smaller wrench to decouple the steel fittings on both ends. The fuel line (steel) that comes from the front of truck is easier to move in order to remove the fuel filter. There are two bolts that also have to be removed (which hold in the plastic fuel filter holder) You'll see these on outside of truck frame.