2002 Chevy Silverado Difficult Start and Service Engine Soo

LEWISPL

MEMBER
2002 CHEVROLET SILVERADO
V8
4WD
AUTOMATIC
123,000 MILES

2002 Chevy Silverado, Z71, 4.8L, Auto, Ext Cab, Short Bed. Replaced fuel pump 2 yrs ago. Since then slight difficulty starting when engine hot. Now it is getting worse. Sometimes will take several cranks and seems like it is getting no gas or spark, but finally cranks. Changed fuel pressure regulator on fuel rail; fuel filter; air filter. Now Service Engine Soon Light is on and OBDII gives code P0452, fuel tank pressure sensor defective. One GM mechanic tells me to replace crankshaft position sensor and one tells me to replace fuel tank pressure sensor.

Monday, April 12th, 2010 AT 3:28 PM

1 Reply

FACTORYJACK

MECHANIC
4,159 POSTS

The fuel tank pressure sensor is for evaporative emissions, has no bearing on starting and running ability. Before I replaced anything, I would check the fuel pressure, you are looking for approximately 60 psi at key on, and it should hold for close to 10 minutes at a rest(after key off). The crank sensor is a logical option, but fuel pressure needs to be ruled out. If it is even slightly lower than spec, it causes problems with vortec engines. The fuel tank pressure sensor may be faulty, and causing the light, but it will not correct your main concern.

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Monday, April 12th, 2010 AT 9:59 PM