My little brother has a '95 Ford Ranger, 2.3 liter with like 175,000+ miles on it. Lately, he's been having idling problems. He says that it only does it when he first cranks it up. The idle will start at the usual 600-800 and a second or two after, it will idle all the way up to about 2000-2500 and back down to 600-800. After a few times of it doing this, it will run fine. He says as soon as he gets it down the road to a light near our house, it will be running perfectly.

He replaced the spark plug wires yesterday and says he notices an improvement i.e. more pep in the truck's step, but it is still having an idling problem.

Can anyone give me any pointers as to what else this may be?

 

First thing to check would be the IAC motor.

 

Well, the engine is suppose to idle high until it warms up (though I don't know if that high is normal). Yeah, check the usual suspects.

 

I know it is supposed to idle high until it warms up. The idle surges. Up and down, up and down like a wave, for about 3 minutes and then it idles fine. You can hear the truck surging. I know it is not supposed to do that.

Last night we took off the IAC sensor because when we unplugged it from the truck, the idle did not lower, which I knew meant something was wrong. We cleaned it, installed it back on the truck, and did the same tests and each time, the idle lowered. I guess it just needed a cleaning, but that didn't fix the idle surging problem.

I would check the 'usual suspects' but I don't know what they are. That's why I came on here to ask.

 

With that many miles he should change the fuel filter,PCV valve,plug wires if they have not been changed. Besides that is the check engine light coming on? Can you hear any vacuum leaks?

 

There may be even more miles on the truck than that. His odometer stopped working about a year ago.

He changed the plug wires Wednesday. That was the first thing he did. I asked him about his spark plugs and he said he took one out and it they was corroded and he hasn't bothered to change them yet.

No engine light is on, no audible vacuum leaks.

Other than the idle surging, the truck runs fine. When the surging stops, it runs pretty damn smooth.

 

Hey Valerie, disconect the vaccum line on the EGR valve and block it off, then start it up and see if any of the symtons change. Do this as a cold start. Does the motor smoke any at startup and then clear out? Is there a lot of blow-by from the valve cover if you pull oil fill cap off?

I am thinking the EGR is sticking from carbon buildup.

 

He said it does blow smoke and then it stops. I'm glad you brought it up because I forgot to mention it.

I don't know about the blow-by. We will check that out tonight when I get home from this hellhole called work!

While I'm thinking about it, I need to say that the idle surge happens everytime he starts it up, no matter whether the engine has been sitting for 8 hours or 8 minutes.

 

OK