Problems with 99 Yukon

[buckeye026]

ok here it is. I have a 1999 Yukon with 147k miles. I have recently replaced the plugs, plug wires, fuel pump, fuel filter, put a flow master exhaust on it, new cats, o2 sensers and an airaid intake system on it. a couple days ago i fired it up and check engin light started flashing at me, I read the codes and its multi cylinder misfire and fuel system to rich. The truck is backfireing really bad and not running well at all. does anyone have any idea what it could be? I am lost here.

 

[imtbear69]

Sounds like it could be a ECM prob or you may have a fowled plug even though you just put it it still might have fowled if you didnt get the gap right

 

[99Yukon_Z71]

Did you change the cap and rotor by any chance. But according to your symptoms and codes, sounds like it probably is your CPI fuel injection system. They are very common to go out on our 1996-2000 Vortec 5.7L engines. The poppets are probably sticking open and dumping fuel. How is your gas mileage? Part number is 63886 and its made by Borg Warner.

 

[buckeye026]

the gas milage is extremly bad.

 

[fyremanpat]

maybe try cleaning the MAF

 

[99Yukon_Z71]

But if you do clean the MAF make sure it is with MAF cleaner spray!! You DO NOT want to use carb cleaner or anything esle as any residue on the filament can cause driveability problems or even damage the MAF. Remember to NEVER touch the filament!!! But I doubt the MAF is your problem. Keep us informed!

 

[buckeye026]

I just ordered a ECM and The CPI Injector system. The truck sounds like its carburated and the carb is is dumping fuel. So I hope this fixes it.

 

[buckeye026]

well I changed out the spyder injectors it cleared everything up. I also had to change out the intake because it looked like the injectors caught fire. they were all fused together. and the intake was melted on the inside.

 

[ravingmadman]

Whoa. Sounds like you narrowly avoided a full-on engine fire. Go buy a lottery ticket!!!

 

[TheBeast99]

hmmm, all these things are something i might want to consider this summer - i'm gonna work on solving my warm hesitant starting issue.