New to the Forum and really need some help

[karmaco01]

Hey Y'all ! I'm new to the forum, coming to you from Dallas, TEXAS...
I have a 1993 Chevy C1500 pickup, 5-Speed Manual Transmission. 6-Cylinder, Throttle Body. Forgive me if I sound like I don't fully know what I am talking about, when it comes to the mechanics of my truck.
.... I don't.
The truck starts and idles okay, but when I start to drive it, I have to really ease into giving it gas and even then the truck just doesn't have much get up and go at all. That's bad enough, but even worse is that before I can get to the corner store and back it just starts acting really stupid. When I try to give it gas, it starts to bog down, sputters, and just will not accelerate at all. And if I don't let of the gas, it will die. I've had to idle all the way back home before... And as soon as I reached the slightest incline in the road, I was stuck.
When the truck does this, if I kill the engine and let it sit for 2-10 minutes, the truck will start up and drive again but immediately starts the whole terrible process again. The truck always starts and idles with no problem. It just won't go.
I have had the fuel pump replaced 5 times already... Because that's the first thing "everyone" days it is. I've had the fuel filter replaced just as many times, I've had the map sensor replaced 3 times. And I have had the fuel pressure checked and checked again. Someone recently told me that it is the EGR Valve sticking and probably a clogged/bad injector. Before I just replace some more parts on this truck, with possibly no positive results...
Any thoughts/help on what is going on with my truck will be so much appreciated.
Thanks so much...

 

[dbrannon79]

Welcome to the forum @karmaco01 will the engine rev up in park or neutral? is there any visible smoke, if so, what color and what does it smell like? one thing that comes to mind is a possible clogged cat or blockage in the exhaust system.

since this is a 93 it's the old OBD1. is the service engine light on when the truck acts up? you can pull codes with a paperclip by crossing two pins in the connector under the dash and count the service engine light flashes (key on and engine off)

Here is a link to a site that explains how to read the codes

Full OBD1 Code List And How To Read Them At Home

In this guide, we will go through everything you have to know about OBD1 Trouble Codes. Learn to read the trouble codes without a scanner and the meaning.

mechanicbase.com

 

[dbrannon79]

Something else you can try that might tell us what is happening. If you cannot rev it in neutral or it seems to bog or sputter trying to rev the engine, get you a can of berrymans B-12 spray or a can of "Flammable" brake cleaner.

BUT PLEASE DO NOT use gasoline in a squirt bottle and keep your face out of arms way of the throttle body, if it backfires it will send a flash ball of fire up and out!!

Pull the air cleaner off to expose the throttle body where you can see the twin injectors. Set the parking brake and verify it's in neutral so it won't try to take off on you. start the engine... get out under the hood with the engine idling. grab the throttle and start to rev the engine. when it begins to sputter or bog while holding the throttle give a spray or two directly into the throttle body down the throat and see what happens.

One of two things will happen here.. One it will pickup and rev seeming like it wants to RUN. Two, it will bog even more or possibly kill the engine.

if it seems like it wants to RUN this means the engine is not getting enough fuel which can be a couple of things.

if it boggs worse or kills the engine, this means it's already getting too much fuel which can be other things.

this will lead us to help you on which direction to go. But try to verify the exhaust is clear first and pull the codes on the ECM first.

Before this test is done, I am assuming the shop that did the fuel pump and filter did the preliminary checks like making sure your distributor cap, rotor, plug wires and all the simple things checked out good.

it might be a good idea to tell us a little more about your truck like it's maintenance history (time since it's last tune-up) and how it led up to it's current condition, did this happen over night? started out gradually getting worse over time.. things like that.

 

[Will L.]

Welcome.
Doug set you on a good path, follow his lead.

 

[WarWagon]

EGR Valve sticking

Is this a CA emissions or 49 state? CA has an electric EGR where 49 state is vac operated. A stuck open EGR would stall the engine at idle. (I had the CA electric version randomly stick on me and primitive ECM had NO CLUE.) Vac operated EGR can flop open off idle and give you trouble. Vac operated are backpressure controlled so the vacuum solenoid opens off idle and a valve in the EGR does the rest.

To check a vac operated EGR put truck in gear and bring throttle up just off idle. Powerbrake it and have someone watch the EGR to see if it flops wide open. Alternatively removing the vacuum line to it for testing and engine "runs" would be a dead giveaway the vac valve has failed. The ECM depends on it working properly.

An electronic EGR would not give you the symptoms you have now.

How many miles on it? Has it ever run properly for you?