Would a dead speed sensor cause other problems?

[HankG]

My truck is a 1996 2WD extra cab ranger with the 4.0L engine and 5 speed manual.

My speed sensor has been going out for a while on my truck, the speedometer intermittently starts flopping around between zero and my actual speed. Today it was even worse than usual and the check engine light came on. I read the code and it was P0500, the speed sensor, which wasn't a huge surprise. However, the truck is having some other problems and I'm wondering if they're related or something else. I don't mind not having a speedometer, but I'm starting to get more worried about these other problems.

It is kind of hard to describe since it only happens once in a while. The truck kind of starts to buck like it's running out of fuel but if I give it some gas it'll stop. It mostly happens in low fuel situations like if I'm going slowly in traffic or letting off the gas quickly. It seems to happen most often if I'm coasting in second. I tried to recreate it on my way home today but except for one quick little hitch that went away on its own, I couldn't get it to do it even giving it zero pedal in second. Also, sometimes it idles high, around 2k rpm. Again, this is intermittent and doesn't seem to happen at any particular time and goes back to normal after a little while.

I'm really not skilled enough at mechanics to do an accurate diagnosis, but it seems to me like every once in a while it isn't getting fuel. If that is indeed what is happening, it seems to only happen when I'm giving it very little gas. Could that mean there's something in the line? Maybe the fuel pump is going out? Or the fuel filter is clogged?

Thanks for any help. I got this truck pretty cheap and I just want to drive it 'til it dies, but I'd like to postpone that as long as it's cost effective to do so.

 

[phantomlord]

I have a 98 Ranger. My speedometer gets flaky sometimes (haven't had time to do a full diagnosis, I think my problem is a short in the harness under the driver's seat). When it drops out, I feel my engine bog down and horsepower drop and when it comes back on, I can feel the engine go back to normal. Sometimes it'll short in rapid succession, at which point, it produces a very noticeable bucking.

Your high idle is probably due to the IAC getting dirty. It's an easy fix that requires removing two bolts and cleaning the sensor. I've had that problem as well.

 

[AllanD]

be very happy you don't have an automatic trans...

 

[killj0y]

Start with the basics like fuel filter and pressure.

 

[killj0y]

Mine does the intermittant high idle, even after a through cleaning of the iac, maf, and a few other things

 

[orangealpine]

For the past twenty years, Detroit has been using vehicle speed as part of the computer's data base to make fueling and spark adjustments. You know the speed sensor is flakey, why spend money on things that might be bad when you know you have a critical part that is?

Bill