hey guys, I have a 1999 GMC Jimmy SLT. I'm very familiar with all the fuel injection problems as I had a Chevy Blazer spider go out twice. Now on to the problem. Im sure this problem has been repeated many times but I cant find one identical to mine


When starting the engine in the morning while cold, it fires right up with the turn of the key. The idle is kind of rough but not horrible. The real problem starts when accelerating from a stop, the engine bogs down and sputters like crazy. It will shift to the next gear and sound fine but when it gets to the higher rpms it will sputter and hesitate. Now when the truck has been driven around for apprx and hour or so, the misfiring will dissipate and it will hardly be noticeable with an occasional hiccup when driving at about 60mph. The DTCs are P0171 lean condition bank 1, and P0300 multiple cylinder misfire. I took the upper intake off and saw that around the cylinder 1 injector there was no carbon due to fuel rinsing it off. The picture that I posted is after I put the intake back on because I forgot to take pictures with it off...I didn't see any fuel around any other injectors besides this one. These are the questions I have

Will the PCM inhibit 4th gear if it detects a misfire?
Will one faulty injector cause a MULTIPLE cylinder misfire?
Will replacing just one of the poppet injectors cure the problem? (yes, I understand that replacing the entire spider will save me work in the longrun)







Thanks guys let me know what you have to bring to the table.

 

Being it says its a lean condition it would not be getting enough fuel..

But on a side note when is the last time you tuned her up with new plugs wires cap rotor and ignition coil?

Sorry I didn't really answer any of your questions bud.

 

I gave it a tune up about a month ago because these problems were current, plugs, wires, coil, cap, rotor...the coil was original to the truck with 144k.
Im gonna go ahead and assume that the o2 sensor reporting it being lean would lead to a faulty fuel injector because of it leaking and not spraying the correct amount of fuel needed?

 

That's kinda what I thinking.

If your losing fuel at that injector its definitely running lean in that cylinder.

And maybe at high rpms there is to much fuel lost at that cylinder maybe causing another one to run lean and throw a miss code.

Have you ever changed your o2 sensors by the way? If they get real worn out it could be telling your computer its running rich causing the computer to lean out the mix. when its actually running fine.

 

yeah I changed them about 2 months ago. do you think the problem would be fixed if I changed that injector?

 

Maybe.

I think you can just by an injector o ring.

That could fix the leak, but if I had the injector out I would try and take it to a nearby rebuild shop or something and have them test it (if you can im not sure).

Or go ahead and replace it if you got the money. If your tight on cash id go with just the o ring.

$3 o-ring, injector is around $60 and $200-$300 for whole new spider and injector assembly.