Diagnose - 2,500 rpm Stumble Miss - 1991 8k mile ZR-1 - ZR-1 Net Registry Forums

SteelBlueZR1 · 02-25-2013

My 1991 ZR-1 with 8,500 miles has developed a stumble, miss, lack of fuel feeling right at 2,500 rpm at all times, except when feathering the throttle to avoid engaging the secondaries. Right after the stumble, the engine starts pulling again, but not as hard or smooth as normal.

Do you think this is fuel pump failure related to sudden demand for fuel when secondaries are engaged? Any help or ideas are appreciated.

Note that the car sat for 20 years and has 16 new SS Delphi fuel injectors, and car driven weekly since I bought it 2 years ago. Symptoms started last week after filling up gas tank, and prior owner apparently left gas tank low or empty while storing (rusted fuel sender?). Car idles fine, but is a bit slow to start.

02-25-2013	#1
SteelBlueZR1 Join Date: Aug 2011 Location: Evergreen, Co. Posts: 346	Diagnose - 2,500 rpm Stumble Miss - 1991 8k mile ZR-1 My 1991 ZR-1 with 8,500 miles has developed a stumble, miss, lack of fuel feeling right at 2,500 rpm at all times, except when feathering the throttle to avoid engaging the secondaries. Right after the stumble, the engine starts pulling again, but not as hard or smooth as normal. Do you think this is fuel pump failure related to sudden demand for fuel when secondaries are engaged? Any help or ideas are appreciated. Note that the car sat for 20 years and has 16 new SS Delphi fuel injectors, and car driven weekly since I bought it 2 years ago. Symptoms started last week after filling up gas tank, and prior owner apparently left gas tank low or empty while storing (rusted fuel sender?). Car idles fine, but is a bit slow to start. __________________ Bert Rankin 1991 ZR1 Steel Blue / Steel Blue #1029 Haibeck chip, slotted rotors, camber brace, C-beam plates, OBX exhaust, Nitto NT555 tires [SIGPIC][/SIGPIC]