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Ask GM Tech (Cam) Your Own Question
GM Tech (Cam)
GM Tech (Cam), Chevy Technician
Category: Chevy
Satisfied Customers: 15181
Experience:  GM Grand Master Technician 2007. 14 years experience.
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99 tahoe 5.7 have replaced plugs, wires, cap and rotor,

Customer Question

99 tahoe 5.7 have replaced plugs, wires, cap and rotor, distributer, coil, control module, spider injector, and each leg, cut out cats, and changed fuel pump and fuel filter, changed egr, and crank sensor still have a random misfire seems I can't win with it
JA: Are you certain it's the fuel pressure sensor that's in need of attention? What about the fuel rail? Have you checked it yet?
Customer: There is no fuel rail to check???
JA: What year is your Spider?
Customer: 99 Chevy Tahoe
JA: Are you fixing your Spider yourself? What have you tried so far?
Customer: 99 tahoe 5.7 have replaced plugs, wires, cap and rotor, distributer, coil, control module, spider injector, and each leg, cut out cats, and changed fuel pump and fuel filter, changed egr, and crank sensor still have a random misfire seems I can't win with it
JA: Anything else you want the mechanic to know before I connect you?
Customer: No
Submitted: 7 months ago.
Category: Chevy
Expert:  kalamykid replied 7 months ago.

Have you tested the fuel pressure?

Customer: replied 7 months ago.
I just changed fuel pump and filter have 65 at key on engine off and about 58 running
Expert:  kalamykid replied 7 months ago.

When you replaced the spark plugs, did any of them look cleaner then the rest?

Customer: replied 7 months ago.
No they all looked really good a nice cream tan color
Expert:  kalamykid replied 7 months ago.

What all codes are being set?

Customer: replied 7 months ago.
P0300 that's all
Expert:  kalamykid replied 7 months ago.

Can you drive the truck for about 15 miles and see if any new codes will set?

Expert:  kalamykid replied 7 months ago.

The hillier the better as to but a load on the engine.

Customer: replied 7 months ago.
I drive it every day about 30 miles and no other codes
Customer: replied 7 months ago.
I have tried it don't set any other codes
Expert:  kalamykid replied 7 months ago.

Have you run a compression test?

Customer: replied 7 months ago.
about 142 to 148 per hole
Expert:  kalamykid replied 7 months ago.

What brand cap did you use?

Customer: replied 7 months ago.
I had a autozone cap and then I bought a complete GM distributer and put in with cap and rotor
Expert:  kalamykid replied 7 months ago.

How many miles are on the engine?

Customer: replied 7 months ago.
Has about 155k
Expert:  kalamykid replied 7 months ago.

Have you check for timing chain slack?

Customer: replied 7 months ago.
No I was hoping not to have to go there but that was my next guess
Expert:  kalamykid replied 7 months ago.

All you have to do is pull the cap off , rotate the crank shaft by hand two full turns clockwize, then mark the rotor button as well as a place on the ballancer and timing cover, then turn the crank counter clockwize and see how far you have to turn the crank till the rotor button moves.