Alright here we go. 91 trooper 3.4 v6, tbi swap, intake bored, 3.4ht cam, with gm spring kit, 1:6 roller rockers, gm high volume oil pump. Timing around 14deg. After market fuel reg-running around 11psi at idle.
Thats the goods, here's the problem.

After the swap i have oil pressure out the roof, it pegs the factory gauge(110+ psi)didn't have this before.

Constant stalling, while changing gears to slow down it dies, but if you stay in the gear until 1000rpm and then push in the clutch it will idle.
This really sucks because when someone pulls out in front of me and i push in the clutch to stop quickly it dies <img src="/forums/images/graemlins/angry.gif" alt="" /> <img src="/forums/images/graemlins/angry.gif" alt="" />

Since this build the truck doesn't seem to run as well as the last 3.4 that was just stock except for the tbi swap, any help or idea's would greatly appreciated. thnx

I think that you have multiple problems that aren't necessarily related.

The oil pressure indication sounds like an electrical problem, wiring and/or sending unit.

The stall problems could be a million things, but I would start with carefully checking all your vacuum lines and connections. I would particularly check the TBI to intake manifold seal.

Thanks for the reply.
I have checked the tbi base gasket, which was replaced during the build. I preformed the carb cleaner test and zero leak was found.
The gauge on the other hand, has good wiring and I will replace the sending unit asap. I don't like throwing parts at something unless I know whats wrong first. The part probably isn't to expensive but will see. Thnx

First get the fuel press, adjusted up to where you are running around 16-18 lbs at idol, 11 lbs is too low even for a stock 2.8 or at best marginal, i think you will see a big diff, in the running of the eng, at that low a press they don,t like to idol very stable when cold. Jerry

Well I don't agree with that high of fuel pressure. The stock set up is a spring regulated 9-13 psi. Gm can't validate which spring provides which pressure. The ecm will control the pulse width which will provide me with more or less fuel as it see's fit. That pressure causes me to run way to rich, been there done that. With the addition of the aftermarket regulator I can set a consistant pressure which my engine seems to run best around 11-12psi. thnx

MAYBE should take at look at the PLanet Isuzu board there is a complete article on raising the fuel pressure by Sam Jelinick that seems to coroborate the pressures i mentioned , and Sam pretty much knows what he is doing

Jerry also was a tech instructor for Isuzu for more years than most people here have been alive.

I am in no way trying to doubt anyone's credentials. I am only going off of what I have seen. The plugs are golden brown at my stated pressure, and are black at the other stated pressure (16psi and up). That indicates to me richness... My Mastertech scanner shows way rich at the stated 16-18psi. Also this pressure killed a new o2 sensor, the scanner showed it dead in the water. It was switching before the increase in pressure. These pressures cause my engine to run way to rich. I read the article on the P-I website. There is no mention of the setup he was running, only that he was complaining of poor idle. My truck idles fine at 850-900 rpm, it just has an interm. stalling when disengaging the clutch. As far as the oil pressure, my bearing clearances were to close for the oil I was running changed to a much thinner oil and now the gauge is reading correct. Thanks for the replys...

Did you adjust minimum idle air and TPS voltage yet? These may have a big effect on the stalling issue.

You also might try installing a heated O2 sensor, there are discussions on the S-Series.org 60 Deg V6 board regarding this. The heated sensor keeps the engine in closed loop longer and the hot sensor provides a more accurate air/fuel input to the ECM.

If your speedo needle is wavering at slow speeds, you might try pulling the drive cable out and lubing it up. A wavering speedo sends a goofy signal to the VSS buffer which causes some Very Strange Stuff. My old '90 2.8 was running funny and throwing Check Engine lites until I lubed the speedo cable.

What kind of spark plugs are you running, if Bosch throw them away! These motors like the AC-Delco Rapidfire plugs, the standard (non-platinum) ones are cheap enough and work very well.

Check your EGR for deposits/sticking as a partially-open EGR at just-off-idle could cause stalling.

HTH and let us know what you find...........ed

Hey thanks Ed for the reply. I have adjusted min air, and tps voltage. As far as the speedo goes no it doesn't bounce or do anything funny. The plugs are Ac Delco RS the kind specd for the engine. The egr ports and valve was cleaned during the build, and it is functioning properly, thanks for the idea's though. I'm thinking about moving the pressure regulator closer to the tbi for a better reading. It might be giving false reading due to it's current location. Thanks for the reply