I have over 177,000 miles on my 2001 Ford Ranger XLT 2.3L DOHC 4 Cyl truck. I have almost without fail, been getting about 20-24 MPG.

This past week I drove it to some place. I turned off the truck. Walked away and about 3 minutes later got into my truck, started, and it was running rough. Prior to this, no issues. No rough idle, no smoke, no real oil used, nothing.

Idling the truck sounds rough and shakes. While driving, slow speeds (under 35) I don't seem to have much power. Once I get it into 4 gear, no issues at all. When I slow down to make a turn (like approaching a stop), the RPMs drop to like 800 and acts like it wants to choke out. It is burning more fuel during this rough period (but only in this rough period).

Checks:
- Changed plugs and wires
- Air filter is good
- No water in oil
- NO error codes
- Did the soap test and no vacuum leaks
- Pulled plug wires
Cyl 1 and 4, no idle change. Cyl 2 and 3, idle changes
- I get fire in the distributor (initially I thought it was this, no change when I changed the part)
- I put some Heet in the gas tank in case there was water and drove it about 12 miles, some improvement to what it was, but still idling rough.

Questions:
1) I would like to do a compression test. What compression should I see? What compression level would indicate concern?
2) If compression checks out fine, what else?
3) If compression is low in cyl 1 and 4, then what?

 

Check throttle body and IAC for gunk. This is most likley...

Use ether not soap to test for vacuum leaks if that fails.

 

Question: Will the butterfly suck your hand in or feel any air suck in when the truck is on?

A new development occurred. The line that runs from the exhaust to the EGR valve had a crack in the hose. I sealed that (as a test) with electrical tape.

I had a mechanic tell me EGR valve could have carbon on there and that is what is causing the problem. I can clean the throttle body by taking that out to see if that fixes the problem. When my dad manually opened the valve, it seemed the idling improved (like the engine was sucking more gas (and flooding itself) than air). So is that the throttle control sensor, Idle control sensor, EGR, or a combination of these...or something else?

 

Update:

Although it has been running rough, I have been driving it some. when I cut it off, it acts like it's choking because it sputters and shakes the truck.

I cleaned the throttle control and the chamber behind it that goes into the engine. It had quite a bit of grime and carbon build up. When I was getting to this part, I disconnected the MAF sensor and the throttle position sensor.

I turned on the truck (with the throttle completely off). The truck started, ran about 5000 RPMs, idled about 2300 and then cut off. Strong gas odor from tail pipe. Tells me I am suck a lot of gas right now.
I installed the throttle body back onto the engine and cables, but not the sensor. It idled about 1500 for about 20 seconds (I could hear air being sucked somewhere) and the air sucking stopped, engine idled around normal and then engine cut off. I, though, noticed the engine cut off like it normally did...nice and clean (meaning no sputter).

I connect the sensor (no air tube or anything connected) and the truck ran with a little bit of a rough idle but not too bad. I connect the tube and everything back tight (except the MAF). The truck although a little rough in the idle, seemed like a normal running truck. I noticed I forgot to plug in the MAF, plugged it in and the truck idled hard. I unplug it, idle smooths out, plug it in and the truck idles rough (like a Chevy, just kidding, I'm a Ford guy).

So, I may have another issue to help smooth out the idle, but I am really leaning given those series of tests the MAF is the issue for the rough idle.

What do you think?

 

As it turns out, the MAF was not the problem. Although the throttle body needed cleaning, that was not the problem. It was not the throttle position sensor. It was not a sensor at all. The intake manifold needed to be replaced with a gasket. The hose to the ERG valve also was replaced (and needed to be) although that was not the real problem.

 

i have a 98 2.5 and have the same problems and have replaced the same sensors and still nothing..