Okay, I'm getting frustrated...

So My 1999 4 door is really getting me this time. I've put a new rebuilt engine in it, rebuilt tranny, most new parts under the hood. Here's my issue..

SOMETIMES, when I start it up and go to accelerate from a stop after warming up or cold, it will bog down and either try to die or it will die, but it's totally random and only happens sometimes. Also, I'll be driving down the freeway sometimes and suddenly it will bog down and the rpms will drop and suddenly I'm on the shoulder of the road with the same acceleration issue, OR I can get it moving again, BUT it will only hit 1200 rpms in 2nd gear, usually around 25-35 mph, but no more. I also have noticed a weird shifting time when it's accelerating, that may just be due to my easy acceleration so it doesn't die, but when I do try to accelerate more quickly and it doesn't bog or die, it will have very little power, and will sometimes stick at about 2000 rpms. I've gotten the engine light a few times and the codes are usually System Too Lean in Bank 1 & 2, O2 sensors Bank 1 & 2, Idle Air Control System RPM High. But sometimes a random EGR code or something, but not in a long time.

So What I have done!
-Changed spider injector between the two sets that I have from both engines
-Been running Fuel System cleaner through it
-Checked fuel pressure, sat at about 58 psi
-pulled CAT if it was plugged, must not be
-Changed the MAP sensor since I broke the seal on the old one
-Also got a new elbow where the Brake Booster pulls vacuum off the intake since my oring was shot and caused a vacuum leak

I'm running out of ideas.. Please help!! Someone told me to replace the TPS or O2 Sensors but I just want my issue solved.. I've died too many times in the middle of intersections and been late to work too many times!

Thank you!!

 

Merry Christmas guys, but does anyone have an opinion on my issue?

 

i had similar issues with my 95 jimmy
hard to start,random ran like crap.

the fuel pumps in the tank go bad alot
and can cause this to happen.

when you test the fuel pressure (58 sounds low should be over 60?)
does the system hold the pressure for a long time like for 10 min.
or does it drop like a rock?
if it drops,
test the pump pressure down at the fuel filter.
mine still wouldn't hold any pressure there either
that says the pump is shot.
so i changed out the tank fuel pump
and now it runs great,starts on first crank..
stick with ac delco pumps
the others do not last long! damhik
if the fuel pump cks out ok
clean out your egr valve,that would be the next culprit

 

Check your mass air flow sensor. I had a similar issue and replaced it. never happened again.

 

I broke down and am in the process of replacing the fuel pump and fuel filter. What a PITA...