Hey everyone. I’m back with another issue with my 1999 Suburban I am trying to revive. It has been running great until today when I started it and idled real rough. I watched it for a minute and then put it into drive. Everything was going great until it got to about 2000 rpm and it started sputtering and losing power. I was able to limp it home but it’s still struggling. I would have to restart it several times and each time it would seem to drive ok until about 1000 rpm when it starts sputtering and eventually stalls again. I was able to get a video of the issue and posted it below. I am a novice (this is my first project car) so I have no clue where to start so any help or guidance would be super helpful!

Also, I didn’t realize just how dirty the inside was until I filmed that. Several years of sitting outside will take a toll I suppose

 

You need to check the fuel pressure both with the key on and the engine off and also with the engine running.

 

I'll tell ya, had the same issue with my 1998 Subrbn, and it ended up being the fuel filter.

 

How many miles on your fuel filter? My 99 suburban book says change every 30,000 miles.

 

Replacing the fuel filter is inexpensive, and a good first thing to do. I will say that on our 1994 Suburban that GM chose to have the two fittings 16mm and 20mm (if I remember correctly) so I had to use Vise-Grips because none of the metric or SAE wrenches in my sets would fit (I later bought 16mm, 18mm, and 20mm stuff, not in the sets, at least when I bought mine.

 

It’s been a minute but I’m back again. Turned out the super cheap fuel pump I put in failed. Now that I know it has the potential to run again, I put a Delphi unit in and pressure has been great. The GM Genuine fuel filter I put on has maybe 3 hours on it with approximately 10 miles.

Since that’s been fixed, I have been chasing a misfire between 3 and 7. Changed plugs because they were old, distributor cap because of corrosion, checked compression that returned great numbers, and changed out the injectors for the MFI version instead of the central port. The first crank took a while before the engine started and immediately cylinder 6 showed a misfire as well as a MAP failure. Found I forgot to connect the MAP connector so I corrected that and restarted. Cylinder 6 still shows a misfire and this one happens at idle where 3 and 7 were under load. I also developed a sticky throttle body and and when I push the accelerator more than half way in park, the engine stalls. Sometimes it recovers, other times it dies completely. Last time I checked the fuel pressure, it was in the 60s and I’ve also swapped plugs but 6 still misfires regularly. I’m thinking of taking the upper manifold off again to check the injector but I didn’t notice any tabs like the poppet style for removing the injector. How do you remove those? Any other guidance is always appreciated!