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Mike S.
Mike S., Chevy Mechanic
Category: Chevy
Satisfied Customers: 7011
Experience:  ASE Certified Master Technician
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1997 chevy silverado,misfire on cylinders 4,6,3,5...Replaced

Customer Question

1997 chevy silverado,misfire on cylinders 4,6,3,5...Replaced plugs,wires,cap,rotor,updated injector housing,and also removed distributor to check gear. I have full fuel pressure. I also have to press the gas pedal a bit to get it to start up. It will idle but barely.
Submitted: 7 months ago.
Category: Chevy
Expert:  Mike S. replied 7 months ago.

So basically the cylinders in the middle are all misfiring. Is this the 5.7 and is it a throttle body fuel injection? If so, have you looked to see if both fuel injectors are working?

Expert:  Mike S. replied 7 months ago.

This is a SFI, isn't it?

Customer: replied 7 months ago.
5.7 liter.csfi i believe,i just installed the updated spider injector unit.
Expert:  Mike S. replied 7 months ago.

Did you have these misfires before that?

Expert:  Mike S. replied 7 months ago.

Have you checked for spark on those cylinders that misfire?

Will it run better for a few seconds with a few shots of starting fluid into the throttle body?

Customer: replied 7 months ago.
All misfires were present before doing anything to the vehicle,nothing has changed. I did check for spark on those cylinders with spark tester and they all seemed good. I have not tried spraying anything into the throttle body yet. I have a new fule filter on the way,and once i get that installed i can try that.
Customer: replied 7 months ago.
The customer has stated that he was just driving normally and was accelerating up a hill and once at the top of hill it started misfiring like crazy and running rough.
Expert:  Mike S. replied 7 months ago.

Yeah, if dirt has somehow made it past the fuel filter, which I don't know how it could, I suppose the poppets I believe they are called may be clogged. I assume they can be cleaned but personally, I have never done so.

If after the fuel filter and it runs better for a few seconds on the starting fluid, I would see about cleaning them poppets.

Customer: replied 7 months ago.
I just replaced that whole injector unit,it is the upgraded unit with the actual injectors.
Customer: replied 7 months ago.
I just replaced the whole injector unit with the updated one, It was around 300 bucks. it hasnt been in there an hour yet.
Expert:  Mike S. replied 7 months ago.

Ok, what abo a compression test to rule out a blown head gasket on each bank?

Customer: replied 7 months ago.
Havent performed a compression test yet. The fuel filter just arrived so i will install that and see what happens.
Expert:  Mike S. replied 7 months ago.

ok

Customer: replied 7 months ago.
I previously did a compression test which i failed to mention. My fault. They were all between 175-190 on the gauge. At this moment i have already tried everything you mentioned before you even suggested it,so with that being said i am not satisfied with results thus far and do not believe i should get charged for this!
Expert:  Mike S. replied 7 months ago.

You are not getting charged, you only made a deposit. You only get charged if you give me a good rating otherwise you can ask for your deposit back. Is that what you want to do? If so, you have to contact customer service. If you would rather continue, have you suspected a vacuum leak and checked for one, like a huge one?