I've got an all stock '93 Z-28 5.7L automatic with 133K mi. Idle is fine (smooth) and gentle cruising regardless of speed (0 - 70mph) where very light pedal pressure is held steady (smooth too). But, upon any harder acceleration, I'm getting the most God-Awful sputtering misfire I've ever encountered! I swear it's like somebody yanked four friggin plug wires off until I let off the pedal! And it rocks the car to the core!
I know the motor is getting adequate spark and fuel (idle and light cruise, runs almost perfect). Chevy installed all new plugs and wires and although before the visit I found a very slight bit of oil that has leaked on bottom part of the distributor "opti(?)" all else seems fine. Can someone please share what the heck might be going on here? Why would it run so smooth during idle, neutral revving and light cruise but, then suck like hell while in gear under a load?
The Chevy dealer ruled out the distributor (a month ago) when it was misfiring even worse (this was due to a couple of bad wires, tho and ran great for 3 weeks after that fix). NOW, it's bucking and kicking like crazy until I let off the accelerator some (and it's getting progressively worse everyday it seems). Recently, Chevy said they need to replace the distributor AND WATER PUMP because they saw some oil drippage (only on) the base of the distributor unit. They said: "It's notorious for these cars" (and I believe that part) BUT THERE WERE NO LEAKS AROUND THE WATER PUMP AT ALL! I checked before and after that visit.
FYI, the SES light has been on with no performance problems since I've owned the car (over a year now) and ran beautifully. The previous owner said the MAP sensor was removed when installing the K&N intake system). But, I don't know how to check for "codes." So, I feel stuck and vulnerable to dishonest techs. Hey, sorry for the article here. But, any ideas why I'm getting this horrible misfiring? Any help is appreciated.
Hawk
I know the motor is getting adequate spark and fuel (idle and light cruise, runs almost perfect). Chevy installed all new plugs and wires and although before the visit I found a very slight bit of oil that has leaked on bottom part of the distributor "opti(?)" all else seems fine. Can someone please share what the heck might be going on here? Why would it run so smooth during idle, neutral revving and light cruise but, then suck like hell while in gear under a load?
The Chevy dealer ruled out the distributor (a month ago) when it was misfiring even worse (this was due to a couple of bad wires, tho and ran great for 3 weeks after that fix). NOW, it's bucking and kicking like crazy until I let off the accelerator some (and it's getting progressively worse everyday it seems). Recently, Chevy said they need to replace the distributor AND WATER PUMP because they saw some oil drippage (only on) the base of the distributor unit. They said: "It's notorious for these cars" (and I believe that part) BUT THERE WERE NO LEAKS AROUND THE WATER PUMP AT ALL! I checked before and after that visit.
FYI, the SES light has been on with no performance problems since I've owned the car (over a year now) and ran beautifully. The previous owner said the MAP sensor was removed when installing the K&N intake system). But, I don't know how to check for "codes." So, I feel stuck and vulnerable to dishonest techs. Hey, sorry for the article here. But, any ideas why I'm getting this horrible misfiring? Any help is appreciated.
Hawk
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