95 Jimmy Questions....

Ok, so i recently got a 95 jimmy, excellent shape, well maintained, but has 300000+ kms on it. Its a 4.3ltr, 4x4, 4 door. The truck runs excellent for me sometimes, when its running good its got lots of power, smooth quiet ride, no worries. But she likes to run rough for me, rough idle, noisier, wanting to stall when coming to a stop( i've taken to putting it in neutral at stop lights to keep it from stalling, seems to smooth out the idle), seems like its misfiring, but once i get going again its all good till the next red light. Looking through these forums has been very helpful, thank you to all, but i just can't seem to get it going good. Since i've gotten it i've done oil change (running full synthetic), new muffler(for saftey inspection), cap, rotor, coil, plugs, wires, air filter, fuel filter, have taken the egr off and cleaned it, replaced tps sensor, taken iac valve off and cleaned. Now mind you, this was not all done at the same time, but it seemed like everytime i did something with it, it would run a bit better, the biggest difference i noticed was when i did the tps sensor, thought i had it cured but then it started again. And now this evening, my landlady knocked on my door to tell me that my signal light was on, my hazard switch is broken. So i went out started it up to charge the battery up since i did not know how long it was on for, and went looking in the back for some cable ties to hold the hazard switch down to keep them off, and i notice the exaust was very rich smelling, lots of carbon in the tailpipe and even a little bit of a black spot on the ground under the tailpipe.
So i come to you guys, what should i look at doing next to get her running right? I'm good at working on it, just not good at diagnosing lol, am use to carborated engines. I was thinking of hitting the junkyard to look for a egr valve as i don't really want to drop the almost 300 bucks it is for the new one, and when i had that out to clean it the pintle would stick even after a very thourogh cleaning. I read somewhere on here about the idle air bypass hole getting clogged would cause these same things as with mine? But for the life of me i cannot find the thing. Any suggestions? Please help, i've got a good paycheck and a weekend off(i hope...) and i'm hoping to get her fixed this weekend. Thanks in advance.

Two or 3 things to check besides the basic secandary ign system.

Complete Fuel pressure test.
Check egr valve for carbon balls.
Check dist shaft for sideways play.
Any codes or check engine lights?
A lot of good sensor information with a good engine capable scanner check.

I'm going to see about getting my hands on a scanner to pull the codes this week, the check engine light does come on ocasionally, but usually doesn't stay on. What kind of stuff do i need to do the fuel pressure test?

I'm going to see about getting my hands on a scanner to pull the codes this week, the check engine light does come on ocasionally, but usually doesn't stay on. What kind of stuff do i need to do the fuel pressure test?

A good fuel pressure gauge with the GM scrader valve hook up.
For fuel pressure specs we need engine code?
Post back engine code.

Engine code is W, and thanks for all your help on this and on my other thread too

you are welcome and let us know how it goes.
Fue pressure specs on the 95 w code 4.3 is 55/61 lbs of fuel pressure.

The only true test on a fuel pump is to check the direct fuel pressure from fuel pump.
A quick test is to block off the return line and see if fuel pressure comes up to 75-85 lbs.
But do not run the pump at full pressure very long.
Also when testing fuel pump and pressure you need to tape a gauge to outside windshield or outside mirror and drive it on the road for 20 -30 minutes
Until the pump gets has run a while to check for a pump fading out after hot.

Hard to start cold or hot and fuel pressure testing guide lines.
Check cold start fuel pressure.
Check engine running fuel pressure.
Check engine running on the road fuel pressure.
Then shut it off and watch for fast leak down.
Pinch off at rubber part or block off return line and check full pressure.
If pump has full pressure with return line blocked and low pressure without it blocked most usually the fuel pressure regulator is leaking or not holding pressure.
Later V6 and V8 gm engines should have 60-66 fuel pressures.
Cold start should be 64-65 lbs of pressure.
The 95 or yours is 55/61 lbs pressure
If you do not have full fuel pressure on a cold start the injectors will not squirt fuel.
Do not leave home without it.
Engine running should be 55/61 lbs pressure depending on engine load.
Full pressure with return pinched off should be 75 or more.
And if it has a fast leak down after shut off you have a leak in system.
Post-back fuel pressure readings.

Remember a fuel pump pressure regulator controls the pressure and maintains a steady pressure depending on engine load and vacuum.
It has to be capable of producing higher pressure than the regulated pressure.

The fuel pressure controls pressure and can leak off or bypass pressure

Post back your fuel pressure readings.
MT

K i'm going to get a fuel pressure gauge tonight hopefully, had no luck finding one this afternoon, will post back my reading after i find one

So i picked up what seemed to be the last fuel pressure gauge in town tonight, the line is a little short but it'll work. I'll do the checks on it tomorrow after work as i have ben running around with it all night trying to find the gauge. just a quick question though, you said to check direct pressure from the fuel pump, do i do this just by connecting the gauge to the schrader valve and turn key on but engine off or engine running? And where is the return line i block off located at? Sorry if these are silly questions i just don't want to have any problems and make sure i get accurate readings when i do this. Thanks so much

Just did the fuel pressure test, key on went up to 58, dropped down to 50 after a few mins. Started it up was up to 56-58, and then took it for a drive, and of course it didn't act up as bad as it usually does, but it did idle rough for me and want to stall a few times, but the fuel pressure remained constant 56-60 the whole drive even when rough idling and stalling, oh and no fast leak down after shutting it off either.

Get it hot and recheck.
Make sure fuel pump will pump full pressure.
MT

I had to do some running around tonight so i figured i'd put the gauge back on and see how she did, ran it for a good hour, it started with the rough idle and stalling out at stop lights like usual, and the fuel pressure stayed the same the whole way through, steady between 56 and 62 the whole drive rough idle and all. One thing i noticed driving it tonight was when coming to a stop if its acting up like its going to stall if i put it in neutral, even if the rpms are right down (like 100) about to die out if i get it into neutral it steadies itself out and i can put it back into drive for the rest of the red light without it stalling. What should i look at doing next?