1999 4cyl rough running

[D1LL0N]

Before I spend the cash/time on changing the fuel pump I was trying to see if I can diagnose why it is running so rough. This is my only vehicle and I rely on it. I also live in an apartment and have basic hand tools. It starts and sputters. It runs pretty rough and gets probably 15MPG if that. Sometimes it will die when sitting it traffic unless I keep a little throttle on it. I did the basic tune up not too long ago and it still ran rough. Any suggestions on what I should check and how I should check it. Need to get this fixed before it fully goes out and I lose my job...

 

[scotts90ranger]

I would start by pulling the codes, autuzone will do it for fee. From there, find the fuel pressure regulator, pull off the vacuum reference hose and see if there is any fuel there, there shouldn't be any, if there is that is the problem. Also, pull off the MAF sensor housing and look at it, if it's completely filthy, that's probably your problem...

 

[RonD]

Yes a dirty/bad MAF sensor can cause a run lean or rich condition
On the 2.5l you can swap coil packs, one is primary the other secondary, if the primary is having a problem it will cause your symptoms, switching it to secondary would reduce them.

A compression test might be helpful

 

[zekew64]

How many miles are on the truck's odometer?

If it's more than 100K, I'd say that perhaps a timing job is in order, to replace the timing belt you have currently.

I say this because my fiancee's 1999 Chevy Cavalier was doing the same thing your Ranger is now--it would run, but there would be times, before the chain (she had a chain, vs. a belt) was replaced. To make a long story short, we drove the car from northern IL to Elkhart, IN, and had the chain finally give up the ghost.

After the chain was fixed, got the car back and it ran good as new--drove it home, no problems. To top it off, the mileage on the old chain was 33K miles over the specified time frame for replacement, which was 150K miles.

Point in all of this is that you probably have a stretched timing belt, which is letting the timing of your truck be retarded too much, hence the fact that your truck runs rough, stutters and spits upon startup.

I would say, as well, that if you replace your timing belt, replace the tensioner as well, just to make sure that the tensioner isn't bad either. What size motor do you have? The 2.3, or the 2.5?

 

[rangergi]

I had close to the same problems with my 2000 2.5. Except it got so bad in 1 day that I had to have it towed home from school. It kept dying on me sitting at lights. Got it home, looked around, ended up being the throttle position sensor. Hope this helps.