Check Engine Light On?

The reservoir was completely empty. So I added coolant and checked the radiator. I started my truck and it is still running rough and the check engine light is still on. We are going to drive it up to the auto store (1 1/2 mile round trip) and get plugs, air filter, oil filter and oil. We will see if it is still smoking through the vent. Any more advice? I REALLY appreciate your help.

The Temperature gauge has never moved from it's normal position. And the truck has never overheated. I only added about a 1/2 quart of antifreeze to the reservoir. And there is no moisture on the passenger side floorboard from which I understand is a sign of a heater core leak. I have neglected to check the coolant but my truck does leak some oil and I do have to add oil every so often. I added the coolant and the truck ran rough for a period of time but then seemed to run normal and the check engine light went out and no smoke came out of the air vent. I'm just having a hard time believing that's all the problem was, do you think this is a sign of the beginning of a bigger problem? Thank you for your time and advice.

Usually takes a few minutes to start when its cold. I turn the ignition and it starts to fire, kinda starts and then shuts off. Usually goes for about 1 minute on that and then it will actually start. Any knowledge? Also, most times when I drive somewhere, my check engine light comes on for about 25 seconds and then shuts off after about 10 seconds. I ran the codes about 3 months ago at a local auto parts dealer. They said the code had to do with my Oxygen Sensor. Not sure if my vehicle has 1 or 2 sensors. But, I replaced the one nearest to the Exhaust Manifold and didn't fix the problem. Also, awhile back I kept getting codes for my EGR valve, which I've replaced 3 times over the last 2 years (which isn't Normal).

It sounds like a vecuum leak but it could also be a bad mass flow air sensor

buy some mass air flow cleaner take off the MAS and clean the wirers on the inside be careful not to drop them or touch them or they could be damaged

then crank the truck up on listen for hissing for a vacuum leak

Well, the thing is that when I take the vacuum line off the EGR valve, the RPMs dont go down or anytbing. And it takes forever to start when the engine is cold. I dunno if maybe that might be my Ignition Module, because it turns over, Starts to fire and then dies. Does that for about 5-10 Minutes every morning. And then after it does start I have to crank on the gas to keep it started, constantly revving the engine when its cold which i know is bad. Also, when I take off for the first time after starting it, usually the exhaust takes on a blue-ish hue and lingers for a little.

You said that the idle doesnt change if the EGR are valve is removed that means the rough idle is not cause by thisvalve

clean the mass air flow sensor with a can of mass air flow sensor cleaner it 7 dollars at advance and it should fix your problem

the blueish hue is from bad valve stem seals

So that would be where my head is at right? What about the takin forever to start? Same thing too? Or ignition module?

Engine Performance problem
1994 Ford Ranger 6 cyl Two Wheel Drive Manual

while driving yesterday the truck yesterday, the truck bucked once and the check engine light came on and went back off. I drove about 1 mile and it did it again. I drove about 15 miles and it did it at least 5 times. Today, as soon as I start the engine the light comes on and stays on. I put a new (REBUILT) motor in it about 3 years ago. We used all the old sensors and injectors because the old motor ran fine. It just used a quart of oil every 150 miles. The new motor probably has 25k miles on it.

While driving the engine will be running fine then suddenly my CHECK ENGINE light will come on my rpms will drop and the engine will start to idel or run erratically. This will last for anywhere form 1 to 5 minutes then the CHECK ENGINE light will go out and the engine will run normally Note it happens about every 30 minutes or so.

I recently was trying to be proactive with a repair and have since experienced multiple problems. I took the truck in and had the lower intake gaskets replaced, I knew they were leaking. When I picked the truck up and drove home, the check engine light came on and the car was idling very rough.
I took the truck back and they said that the Mass Air Flow needed to be replaced, reluctantly I approved the repair and accepted coincidence.
I picked the car up again and while driving home the check engine light came on again, called mechanic and was told perhaps they forgot to reset code.
I took truck back again and said I felt it was still running a bit rough off and on. They said the cleared the check engine light and said the car ran great for them the entire time.
I left the shop and on my way to work today "CHECK ENGINE" again. The truck still feels as though it is surging a bit when I'm at a stop for a few minutes with brake on. Any direction or ideas is GREATLY appreciated.

I'll do that - it goes off when I turn the truck off and then eventually comes back on. Does the check engine light have to be "on" for them to read the code?

The light came back on and I took it by AutoZone, they were not able to hook up the code reader because the truck does not have the plug in for the code machine under the dash. The guy did look under the hood and found a hose that had been torn completely it was a small hose (emmissions) and he thought there was a possibility that this was triggering the check engine light and may have even have thrown a bad code for the Mass Air Flow Sensor which may not have been needed to replace.

I drove back to the mechanic shop and showed him the hose of course he assured me that the Air Flow Sensor was in fact bad and that this hose would not have made a difference (who knows). He hooked up the code machine and it was reading that the oxygen sensors were not functioning properly, one was bad and the other running lean.
I asked if the tube that was broken would possibly alter a true reading on that machine. He replaced the small piece of tubing and told me to drive it for a couple days and see if the check engine light came back on that the tubing may make a difference.

I explained to him about the sporatic surging when I am at a stop light sitting with the brake on. He told me that once the brain (computer) in the car is cleared that it may need to relearn itself and my driving habits and that those symptoms may adjust themselves.

Something new happened last night, the car had been sitting for about an hour and when I started it and went to accelerate it just creeped along and then I heard a clunk under the hood (not like a hard shift) but a strange clunking and then the car picked up speed.

I am not going back to this mechanic - I will return to my old mechanic althought he is not close in proximity, I'll make it work. I guess my question at this point is - does any of what I have been told sound accurate? I've now dropped about $1,000 dollars into my truck and if I don't need to start again with another mechanic I'll wait. Any direction you can offer is appreciated.