90 missing under load at full throttle.
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Joined: Jan 2008
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From: hinton ia
90 missing under load at full throttle.
well my 90 vette seems to miss under load at full throttle only, say I'm driving down the highway at 75mph 6th gear 1200rpm I floor it and it accelerates but misses at the same time, its only obvious at low revs but I can feel it at higher revs too. the fuel pump and filter have been replaced but i have had this problem for a while now. with normal driving it doesn't appear to happen but if I floor it under much load it will start to miss and it will do it in all gears but more in the higher the gear and the more the load. like I said it doesn't do it at like 3/4 throttle only at full throttle or very close to full throttle. the injectors were replaced about 4000 miles ago. my only guess is fuel pressure regulator? if I take that vacuum line off and smell it, it smells like gas but does not appear to be damp. I'm stumped. Please Help! thanks Pat
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Joined: Jul 2007
Posts: 5,043
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From: Tampa Florida
well my 90 vette seems to miss under load at full throttle only, say I'm driving down the highway at 75mph 6th gear 1200rpm I floor it and it accelerates but misses at the same time, its only obvious at low revs but I can feel it at higher revs too. the fuel pump and filter have been replaced but i have had this problem for a while now. with normal driving it doesn't appear to happen but if I floor it under much load it will start to miss and it will do it in all gears but more in the higher the gear and the more the load. like I said it doesn't do it at like 3/4 throttle only at full throttle or very close to full throttle. the injectors were replaced about 4000 miles ago. my only guess is fuel pressure regulator? if I take that vacuum line off and smell it, it smells like gas but does not appear to be damp. I'm stumped. Please Help! thanks Pat
I'd say leaky/bad fuel pulsator module and/or FPR diaphram. You can use a fuel pressure gauge to measure your bleed down times to confirm an issue.
