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K. Wiggins
K. Wiggins, ASE Certified Technician
Category: Chevy
Satisfied Customers: 2992
Experience:  ASE Certified Technician, Associates Degree in Automotive Technology, 15+ years in the trade
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I have a 1995 z71 Silverado. 185k miles. It has a 5.7 with

Customer Question

I have a 1995 z71 Silverado. 185k miles. It has a 5.7 with a miss.(started about a month ago) idling in park (7000rpm) it does not seem to be that bad, but in drive (5000rpm) say at a stop sign it has a pretty good shake. I does not stall so far. I have changed the plugs, wires, pcv, rotor, cap, air cleaner. I took it to a local shop and they adjusted the timing. It seemed to be a bit better for a day or two, but came back. looking on line, they say it could be anything from a fuel filter, mass air , map sensor, etc. oh yea at he shop they said one of the new wires were arcing, #2 cylinder. I replaced it. I was thinking of taking it back to a shop, but want to take it to one with the equip. to find the problem without hrs. of manual labor costs. any thoughts.
Submitted: 2 years ago.
Category: Chevy
Expert:  K. Wiggins replied 2 years ago.
Hello, 95 was a transition year for GM from OBD1 to OBD 2 diagnostics. SO you'll need to find a shop that has either a Tech 2 or one of the snap on "red brick" scanners, the shop will now exactly what you're talking about when you mention the red brick if they have anyone worth their salt there.
What needs to be done is
1. Fuel pressure test
2. Vacuum and vacuum leak test
3. Scope the primary and secondary ignition system
4. Compression test
5. Live data viewed from sensors via scan tool
A scope can be used to do # ***** and 4. The other tools needed will be a fuel pressure and vacuum gauge.
My advice other than going to a GM dealer and shelling out a lot of $ is to find an auto electric shop that does driveability. I worked in this type of shop for many years and this is the type of stuff they specialize in. Labor rates will be more affordable and they will have the needed diagnostic tools on hand. Diagnostic time for this should only run you an hours labor.