OK...Here we go again mechanics.

[Huggybear]

Clean the throttle body! My 95 dodge did the same thing.

[txhunter-1]

I have a 92 with a 4.3. Several years ago it would die and run, then was good, then it would and die off again after several days. I could go to the tank and give it a good whack with a 2x4 several times and it would be good for a while. I finally replaced fuel pump, pick up and sock and it did the trick. You can check the pump by pulling line at filter and turning the key on to activate the pump. Recently, it was running rough like you stated. It must have been bad gas, as I added 5 gallons of super and a little dryer to pull the water out of the tank, did the trick. If it is running rough, I would think it is not the fuel pump, but it could be a stopped or deteriorated sock? Good luck brother.

[COACH_EM_UP]

I have no way to drain 15 gallons of gas.

Do you have an old primer bulb and fuel hose from a boat? If not, you could buy a cheap one for $12. Take the hose and cut off each of the hose, where it attaches to the boat motor and the fuel tank. You have 2 hoses connected to a primer bulb. Stick one end of the hose into your fuel tank and the other into a 5 gallon bucket. Start pumping the primer bulb until fuel starts running into the 5 gallon bucket. Once there is a constant flow, sit back until it is all out. You might need a few buckets. If you want it to flow faster, pump the primer bulb repeatedly until you get all the gas out. Then fill up with new gas and see if that remedies the situation.

[deerplanter]

Do you think you've dropped a cylinder? If it's lost power also it could be on your valves, pull one plug wire off at a time while running and listen for engine change if none on one then that's your bad hole. Oh and use insulated pliers to pull

[Cold 1]

I would try some Heet in the tank to remove the water first.

[hot_rod_eddie]

I have no way to drain 15 gallons of gas.

Duh. Drill a hole in the bottom of the tank.
You can weld the hole back up later ( just use a lighter or something to make sure it is empty before you try to weld on it)





Since I assume you do not have access to an emission analyzer or O2 gauge I would start with the plugs. If they are white "ish" then you are lean. Now, are you getting too much air or not enough fuel?
Seems like you are getting a million ideas so good luck.

[MQ32Shooter]

Wow, did not realize there could be that many possible issues. Good luck man.

[Texas Tracker]

My Nissan d21 pick up did the same thing I went through all the steps spent lots of money and my time trying to figure it out. Ended up being the computer. 1200.00 dollars later.

[denimdeerslayer]

I think that model still has egr valve. Check and see if its stuck .

[Japeatr]

spider injectors

[texaspacker]

MAP sensor
Mass air flow sensor.
Fuel pump/ sending unit. GM truck fuel pumps from 88-99 fuel pumps should NEVER be run with less than 1/4 tank of gas. They will crater because they get too dry.
Catalytic converter. Expensive! If it is plugged up and you live in an area that don't "sniff your pipe" beat the guts out and reinstall it.
Sounds to me like you have some sort of "engine breathing" problem? Not an ignition problem.
Why or how did the timing get off? You didn't pull the distributor? Correct? The timing should not have been an issue IMO.
People also forget. Sometimes new parts can be bad or broken. Just ask any mechanic that works on commission and has had to something two or three times for FREE because he had bad parts. I know I've been there!
Note: To everyone.
Never ever run your vehicle with less than a 1/4 tank of gas. Never.

[Goldeneagle]

Is siphoning it out not an option? I'd rather try a very small amount of bad gas after siphoning out all I could, than 15 gallons

I have no way to catch 15 gallons of gas.

Is that a carb or throttle body? Vacuum leaks on old rubber can drive you crazy. Im not buy the bad gas problem, never had that issue before. Not saying it dont happen.

Throttle body. I sprayed down the whole engine pretty much checking for leaks. Nothing. This just started Tuesday and I filled up on Monday.

Mass air flow sensor?

Don't think this truck has one.

After your tune up did you try to turn the distributor to see if idle smoothed out. I had a 97 do the same thing and it ended up being a worn cam. The gear on the cam that drives the distributor was worn out. I could turn the distributor to retard the timing enough to make it idle.

You probably need to check some more, lots of things can cause idle issues.
Check engine light on?

I reset the timing this morning. The distributor seems fine. It was only off a couple of degrees from what I think is normal wear on the timing chain.

Could be intake manifold leak. Could be many things. Wouldn’t hurt to test the fuel pressure if you have the tool.

I'll check into that. But when I step on the gas, it runs with plenty of power like it is not hurting for fuel.

Do you think you've dropped a cylinder? If it's lost power also it could be on your valves, pull one plug wire off at a time while running and listen for engine change if none on one then that's your bad hole. Oh and use insulated pliers to pull

The plugs that came out all looked the same. If one cylinder was firing different, the plug should look different than the rest usually.

Duh. Drill a hole in the bottom of the tank.
You can weld the hole back up later ( just use a lighter or something to make sure it is empty before you try to weld on it)





Since I assume you do not have access to an emission analyzer or O2 gauge I would start with the plugs. If they are white "ish" then you are lean. Now, are you getting too much air or not enough fuel?
Seems like you are getting a million ideas so good luck.

I'm about ready to fix the problem with a match!

Wow, did not realize there could be that many possible issues. Good luck man.

It will drive you nuts sometimes!

I think that model still has egr valve. Check and see if its stuck .

Yes it does and that is a possibility.


And if things can't get worse, I just lost my balance leaning over the engine. I busted the connector to the IAC.

[HDWRENCH]

Check the Fuel pressure reg . They are known to leak and the reg is hooked to engine vacuum . so it sucks up the fuel leaking past the damaged diaphragm .

Fuel pressure test is in order as well, The reg will increase pressure under load IE low vacuum .


Also the IAC is a stepper motor and they can get out of position due to carbon as well the stepper motor may also be bad . Simple to remove and clean the port and pintel.. SO not pull on it when you have it out . Just clean it , and re install it will move down to zero and come back to its learned position . Now if very dirty it may take a bit to adjust


Also check for good vacuum with a simple gauge .. you can have a leak at the brake booster as well and not see bad brakes in all cases . Trying pluging the line to the booster and see if your idle improves .

[Goldeneagle]

I had the coolant temp sensor crack go bad on my old 95 z
Similar symptoms

A temp sensor cause a rough idle?

[Goldeneagle]

I just drove it for a few miles. Runs like a scalded dog until you come to a stop. It is better though.