My formula hasnt ran right lately and has been sputtering at times. Now the car will not run at all unless I hold my foot on the gas pedal.

What could be wrong? The fuel pump comes on but its making some strange noises. I can keep the car running as long as my foots on the gas which makes me think its not the pump?

Thoughts on what it could be? Thanks guys.

 

Anyone?

 

CLarify a couple of things.:

1. Does it sputter at idle or when you're driving? Both?
2. Are your injectors original/stock?
3. Is your ingnition system stock/original?

 

it would come and go, mainly after warmed up.

They're original injectors, engine has 98k miles on it.

I've replaced everything ignition related except the knock sensor and other sensors.

Car was a roller that sat on e for couple of years, engine came out of a running ta.

 

bad injector(s) or fuel pump. Ohm test all of your injectors first,then if u find 1 bad one,replace all of them.

 

Also purge your fuel rail to make sure you have no air in the fuel lines, those 4th gens are testy when it comes to that and we had that same issue after a fuel filter swap. With yours being an ex roller that sounds like a possibility.

 

 

Is this a MAF engine or SD engine?

 

Maf

 

Is it throwing a code at all while it's running? A bad MAF can cause issues very similar to what you're experiencing. Try unplugging the MAF and then start the car and see how it reacts. When my MAF took a crap, the car actually ran fine with it unplugged, that's how I narrowed it down to that.

 

No codes and the maf is a reman and I've checked it. I think its the tps.

 

Have you ohmed all of your injectors? Check the stickies for how to adjust TPS. You will need a multimeter for both anyway. Then you can test your TPS in the process.

 

You unpluged the TPS, it sets a code and still runs funny y do you think its the TPS? Did you test it?

Dont just think thats whats wrong.

Test your INJs and fuel PSI 1st.

Also, get a GM service manual from HELM.

 

I got gas and put lucas fuel treatment in and now it runs better.

After doing some reading I think its crud in the gas tank. Until I got the engine in the car hadnt seen action since '05 when the tags expired. The engine itself and all accessories only have 98k miles on them so I really dont think there's anything mechaniclly wrong with it.

Is there anything I can do to the tank w/out dropping it? I've been running fuel treatment in the car ever since I got it on the road and it hasnt improved much. It runs great one day and sputters the next.

 

Be sure to put a new fuel filter on it...other than that you'll have drop the tank to properly clean it and get the debris out; and that job is a chore...

And I heartily second TTOP350's advice to get a factory service manual...as a former GM tech I wouldn't own ANY car without one...