What exaclty is a 556?

[scotts93sho]

While driving at highway speeds (80), the car seems like it drops about 3 cyliders (maybe only one). If you press the gas, the car bucks back and forth. Push in the clutch and you can watch the RPMs bounce from 700-1200. THis happens for about 10-30 seconds. Then back to normal. Ran the codes tonight and get a 556. Can someone give my an answer in laymen terms. Do I need a new fuel pump? Might change the fuel filter for kicks. Did a search but did not find any more ideas than that. Thanks for any help.

Scott

 

[sdpatt]

Scott,

You may want to give your local North Houston SHO service expert a call at Jerry's Automotive: 281-999-1461. Sergio Perfetti will give your SHO the best chance of returning to normal. The 556 code is the primary fuel pump circuit. The fuel pump relay in the CCRM (a.k.a. ICRM) may be faulty. It does sound like it could be a loss of fuel pressure due to a loss of power to the pump.

556 (O,M) Fuel pump relay primary circuit fault