92 vandura 5.7 litre hiccups & lurches
#1
92 vandura 5.7 litre hiccups & lurches
At around 30-40 mph the engine wants to kinda jerk/hiccup/lurch until I give it more gas. Runs great at idle and highway speeds. Not the transmission cuz I can make it sputter in park at around the same rpm until I rev it more. Mechanic buddy thinks map sensor or vacuum leak........thoughts?
#3
#4
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Location: Wisconsin
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I would check your fuel pressure. At 30-40 mph you are not turning very high rpms. At highway speed your engine is turning faster and is actually creating a suction to help draw fuel in. I had similar problems with my 88 and 89 Caprices. Both were fixed with a new fuel pump. Each had about 125,000 miles when the fuel pump went.
#5
I would check your fuel pressure. At 30-40 mph you are not turning very high rpms. At highway speed your engine is turning faster and is actually creating a suction to help draw fuel in. I had similar problems with my 88 and 89 Caprices. Both were fixed with a new fuel pump. Each had about 125,000 miles when the fuel pump went.
#6
Mechanic found a rusted out pick up plate under the distributor. Apparently quite common so we changed that. Symptoms still persisted. Unhooked the vacuum line to the EGR valve, plugged it and ran great. He recommended leaving it that way but "service engine" light came on. I installed a new EGR valve and so far so good. Hope others check this fix first.