Hello, new to the board with problems. 4.3 tbi

[mk1shitrocket]

Hey guys hows it going. I have been searching this site as well as a lot of other and reading the book and can not figure this out..
Here's the deal.
I own a 90 blazer with 4.3l tbi has 50k on a goodwrench motor and 200k on everything else.

When i bought the vehicle a few months ago it ran great. but after a few hundred miles and a few 4x4 trips it started vibrating pretty badly from idle to like 3500 then clears up a little bit but not fully.
It does it in park, n, OD, d and etc. Its not u joints but under load it sure feels like it. It also backfires when reving higher between shifts.

The 4x4 trips i went on werent that rough but i did submerge the engine under water on accident. Went through a puddle that didnt look that big but i sunk into it and the water went over the hood up to the windshield. Then a few days later i woke started the truck and it just started that morning.
Feels like its missing or out of balance or something.
I have replaced the following: Fuel filter, cap, rotor, plugs, wires, serpentine belt, air filter, ran redline fuel injector/intake cleaning through it, changed tranny filter and fluid, pcv valve, cleaned egr valve, also tryed spraying upper engine with brake cleaner for intake leaks and there was no change in idle.

Also when i hit bumps or corners it gas gauge drops to past empty and stalls out.

Last things i can think of today i pulled the egr vaccum line and there was little to no vacuum even when revving it up. I also unplugged what i think is the Electric air control solenoid with no difference (its the one with the little filter inside. There is vacuum going in but none going out to the EGR.

fuel pump, eac, or the coil adapter in the distributor? I dont have a multi meter so i can not test.
I am new to domestics and i have no idea i think i have tried everything. I have asked, read, searched with no luck. I am trying to get this thing reliable for my wife to drive but no one seems to want to help me.
Please anyone has any ideas please help..
Sorry for the super long post..
Thanks a lot
Chris C.

[Mikado14]

Your stalling might be in some way connected with a bad connection on the plug at the tank.

Now, as to your other problem. If I have this correct, you submerged your vehicle, left it sit and then a few days later you started it up. Didn't change the oil, didn't pull the plugs and clear the cylinders or in other words, you did nothing but start it.

Have you done the following:

A compression test
Remove all electrical connections and clean

You have to realize that you may have sucked in cold water in a hot engine, not good. Secondly, why did you decide to play U-Boat commander if you needed it to be reliable for your wife to drive? Do the compression test first, find out if you have done any damage to the valvles or pistons.

[mk1shitrocket]

Hey thanks for the reply. but no didnt let it sit for days then start it up, and i dont think it drank too much water. It made it all the way through the puddle and it was a lot bigger then it looked. but it ran fine all the way home and for some more wheelin.
no i havent ran a compression test i need to do that as soon as i get ahold of a tester. i pulled the cap and air filter right after the puddle. then drove it for a day or 2 with no problems, then started it one morning and it was acting up. I also changed everything after it started acting up.
Any other ideas?
Thanks
Chris

[mk1shitrocket]

Ohh yah and the wife wanted to go through the puddle. I wasnt used to driving a rig that doesnt go everywere so i got surprised. Now my Pathfinder goes anywere without problem..

[OverBoardProject]

If your wife wants you to go through a deep looking puddle ask her if she wants to walk through it first, or at least check the depth with a stick first, and if she sayes no be carefull.

I agree, compression test first, you probably partly hydro-locked the motor, and bent a valve a little in the process.

Some of the vacuum hoses are turned on only when the engine warms up a little, so I wouldn't worry about any vacuum problems yet

[busa_4]

are you ready for the bad news? i think you bent your connecting rods when you submerged it in water. definetly do a compression test but i think that is what you are going to find as a problem. as for the electronics under the hood, you will be haunted with electrical problems for life. water and electrical components dont mix and they are practically impossible to repair. its a guarantee, that all insurance companies salvage out water damaged vehicles. good luck!

[mk1shitrocket]

Never thought of using a stick, heh. but like i said im used to my pathfinder going anywere. Im going to have to buy a compresion tester cant find anyone in town that will rent me one or let me borrow one.
Another thing is if i had a bent rod/lifter/valve why would it run fine when reving but vibrates at idle and under load? Last night i sat out there with the motor just a little cooled down and unplugged the eac(ecs?) solenoid and reved her up and it revved up great but stumbled on the way down just a little?
But hey at least the head work is easy on chevy's. Compared to my V-tec Integra. But hey also like i said the air filter was wet but didnt look like much water on the inside of the air box.
Thanks
Chris

[busa_4]

engine runs smoother at a higher rpm regaurdless if it is missfiring because the pistons are going through the firing order so fast that you dont realize there is a missfire. you will never feel a misfire at high rpm unless you have 1/2 or more of your cylinders missfiring. when your at idle your engine is missfiring do to low compression. since your at idle rpm you are going to feel the miss because the engine is rotating alot slower.

[kalamar]

""""""""fuel pump, eac, or the coil adapter in the distributor? I dont have a multi meter so i can not test.""""""""""" hey man meters are cheap as shit at walmart what other excuse do you have?????????