I have a 1998 Ranger XLT with approx 195k miles that is sputtering/running rough at a cold start - typically when the truck has sat for a day or more. The longer it sits, the rougher it runs at a cold start.
Typically it will sputter and run rough for about 15 to 20 seconds, and then it runs normal with no issues. Sometimes it will cut off when it's bad, and I have to start the truck again, two or so times.
I've tried fuel injector cleaner and a new EGR valve with no change. I tried cleaning the MAF sensor by blowing on it with canned air and also cleaning the air filter.

Could this be a bad sensor or is it something else?

 

You have a old truck with a lot of miles on it.

This means there is no magic part to put in to fix your problem.

You will have to diagnose the problem or pay someone to diagnose it for you.

First do you have a check engine light on?

Is there any codes in the computer?

You will need to run a fuel pressure test, a compression test, check the spark plugs while doing the compression test. make sure to measure the resistance of each plug and wire unless they are obviously shot.

My gut instinct is telling me that you are loosing fuel pressure while it is parked.

If the fuel is leaking past the injectors it will flood whatever cylinder the injector or injectors are leaking, this will cause a hard to start problem and rough running condition until the excess fuel is burnt in the suspect cylinders.

Excess fuel in the cylinders could also wash the oil off the rings lowering compression.

Test the fuel pressure with the key on engine off write the results, then start the engine and write the pressure down. finally shut the truck off and let it sit take note of the pressure immediately after you shut it down then let us know how long it will hold pressure for and how far down the pressure bleeds off.

Make sure to check the engine oil level and smell for raw fuel in the oil.

If the oil has a strong fuel smell and seems very thin you may want to change the oil and filter before starting it again and be prepared to change the oil again after the diagnostics and repair.

 

First do you have a check engine light on?
No
Is there any codes in the computer?
No

I may have forgot to mention, it runs rough like this while it's sitting for 15 to 20 sec. It's not while I'm taking off with it or anything.
It randomly started doing this a few months ago. And only does it when it's sat for a day or two. It won't repeat after it's ran fine for 30sec, even with repeated starts. Which is why it seems to me like a sensor of some kind. Like a temp sensor?

I'll check the oil level and smell as soon as possible.

 

It's not gonna be a sensor.

You can't clean your MAF with compressed air, go grab a can of MAF cleaner from Autozone.

It's more likely to be along the lines of Outlaws comments, this is something that happens when it's off for a while - could be coolant slowly leaking into the cylinders, it'll cough/splutter as it cleans that out.
Could be a general combustion leak that closes as things heat up.

What happens if you run it hot, turn off, then wait to start it until maybe, 5 hours later?

 

"What happens if you run it hot, turn off, then wait to start it until maybe, 5 hours later?"
No issues. It only does it if it's sat for a day or longer.

 

So you're saying that if you left it 8 hours (say, whilst at work?) so it's fully cooled down, it will still start and run fine?

 

I will test the timing like that, but from past experience, yes, it would run fine.
I'll try it soon and get back to you.

 

This morning around 9:45AM I cranked it up and let it sit and run for about 10min. It got to normal operating temp on the temp gauge (about half way - the middle of the gauge). When I started it this morning, it ran slightly rough for maybe 3 to 5 sec (not terrible). Then, after those 3 to 5 sec, it was like flipping a switch and it instantly ran fine after that brief period. No white smoke from coolant being burned off, or from oil. Which there never has been any, though.
Oil stick smelled like oil, no fuel.

I'll try cranking it up around 6PM tonight.

 

Before you ran it this morning, how long had it been since it was last driven?


Interested to see how it runs for you tonight, having got it up to temp this morning.

 

Driven was Monday evening 3 minutes down the road and 3 minutes back.
I cranked it up Tuesday afternoon about 5 times for 15 to 20sec testing to see if cleaning the MAF sensor and air filter made any difference.

 

Here's some videos. Title and video description should let you know times and details.

- 10-5-2017 - 6:39PM

- 10-6-2017 - 1:12PM

- 10-6-2017 - 1:45PM

 

On the very rough start, it looks like you might have meant to say it was last ran the previous day, is that accurate?

 

On this one, yes:

 

So I'm kinda having the same problem but it doesnt go away. When the issues first started it was acting exactly like the problems described in this thread. The issues got worse, choking under acceleration running really rough. I have no idea what the problem is, maybe timing chain? Any advice would be nice.

 

I was the OP of this and I still have this truck.
I can't remember, but this may have been an issue BEFORE the exhaust valve got stuck open on cylinder 2 (passenger side) and then found some cracks in my head. May have had cracks in both. I can't really recall.
I still had the problem AFTER replacing the above, but not anywhere near as bad. After it acted up at startup, it ran great.

I was also suggested to turn the key to ON and let it sit a few seconds before turning it over so that the fuel pump can prime/pressurize the system properly and that has helped. Although for your situation with it doing it during accel, I am not sure.