97 K1500 stumbling/bucking

Discussion in 'General Chevy & GM Tech Questions' started by dsquared, May 9, 2012.

  1. dsquared

    dsquared Member

    My 97 Burb w/258K miles is stumbling/bucking mostly when under load or slight acceleration. No codes. Smooth idle. Seemed like fuel issue so I replaced fuel filter and no change evn though i had the same symtoms 2 yrs ago and the new filter was the trick. Not this time. Checked fuel pressure and it was 55 psi at idle and reving the engine to over 3,000 rpm it never dropped below 52 psi. Shut engine down and pressure dropped about 10 psi in one minute. Do you think the fuel pressure regulator could be causing this since this is over the 5 psi in one minute I read somewhere on this board? What other likely causes? O2 sensor(s), plugs/cap even though not enough misfires to throw code? Other ideas?
  2. dipstick

    dipstick Member 2 Years 100 Posts

    Either bad regulator ..cracked line at injector...or fuel pump. Check reg. vacuum line if fuel is present reg. is bad . Or you can see where fuel is leaking at reg.
    While your there check lines at spider to poppets . Be easy they get brittle with age. If neither probably pump.
    02,S will not cause drop in pressure. Neither will plugs ect. If you had a sensor or plug problem would get a check light.

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