Random misfires

[Streetlegal42]

Installed newer engine and my Tahoe is still missing and reads the same codes as the old engine could it be the ecm every thing else has been replaced

 

[exp500]

A little info from you is needed.

 

[Streetlegal42]

A little info from you is needed.

Old engine had a misfire on cylinder 1 it turned out to be a afm lifter, I tore the engine down and replaced the lifters when I fired it back up it was still misfiring and said random misfires so I purchased a low mileage engine replaced all the gaskets, plugs, coil packs, fuel injectors, cam sensor, throttle body, and a new vlom, installed new engine and it reads the same code and misfires smells like it’s dumping straight gas out of the exhaust

 

[BG1988]

Old engine had a misfire on cylinder 1 it turned out to be a afm lifter, I tore the engine down and replaced the lifters when I fired it back up it was still misfiring and said random misfires so I purchased a low mileage engine replaced all the gaskets, plugs, coil packs, fuel injectors, cam sensor, throttle body, and a new vlom, installed new engine and it reads the same code and misfires smells like it’s dumping straight gas out of the exhaust

check the fuel pressure it might be way too high


spec is like 45 psi or so...

 

[Streetlegal42]

check the fuel pressure it might be way too high


spec is like 45 psi or so...

Thanks will do

 

[exp500]

Sounds like your injectors are grounded. Pinched wire. Post codes. You can plug in a couple 194 bulbs into injector harness plugs to test voltage same as a noid lite. Pull fuel pump relay and crank it over.
Also, even tho you have a 99 you have an LS motor Soo for future posts you are in the GMT400 forum now. something Like NNBS or other BS Where ya wanna be.

 

[Streetlegal42]

Sounds like your injectors are grounded. Pinched wire. Post codes. You can plug in a couple 194 bulbs into injector harness plugs to test voltage same as a noid lite. Pull fuel pump relay and crank it over.
Also, even tho you have a 99 you have an LS motor Soo for future posts you are in the GMT400 forum now. something Like NNBS or other BS Where ya wanna be.

Ok I’ll try it but my Tahoe is a 07

 

[east302]

Yeah, you should probably post in the 2007-14 section as they’re probably more familiar with the 5.3 and can offer a more targeted approach.

This section is pretty much for those of us with a 350...close but two generations before yours and not quite the same


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