Just bought this 1990 ranger xlt 140,000 mi. with the 2.3L dual plug 5-speed. Problem is I think it is running rich possibly? Seems to run fine till your under a load (going up a hill, etc.) and I give it gas and it seems to bogg! You slightly feel the engine bucking and lose power. Give it more gas and it smooths out and gain speed. If you let up a little it smooths, almost as if it is getting to much fuel? The tailpipe is very black inside but I can`t tell if it is smoking up hills when this happens without someone behind watching. Ok, this is what I have done: NEW, air filter, fuel filter new plugs & wires (all 8). Cleaned the MAF sensor and housing also cleaned the TPS. No check engine light and I even deleted the cat just incase it was plugged and a new tail pipe. Any ideas? Also, does the other set of plugs do anything for performance or is it only emissions? Would it run fine with those wires unhooked, just curious? Any help would be good, otherwise it's going to have to see a $$mechanic$$

 

Should I try cleaning the fuel system? A mechanic can run a cleaner threw the rails and injectors. I am running out of ideas and money lol? Please help!

 

Bucking is usually a sign of a lean A/F mixture, weak ignition or excessive EGR. When the mixture goes overly rich, the feeling is different. The power flattens out and the engine may misfire but it does not buck.

I would try driving it with the oxygen sensor(s) unplugged to force it to run directly from the open loop tables. If that helps, then the sensor(s) are probably just old and tired. At or near wide open throttle, the sensors are not used and that might explain why it clears up at WOT.

 

Dunno if bucking is the correct word, hard to explain. But it does fall on its face so to speak. I will unhook the O2 sensor and see how it runs tonight. If it runs smoothly I will replace the sensor, right?

 

Ok, I unplugged the O2 sensor and let it warm up. Then I drove about 25 mi. and It seemed to run ok. I had to shift out of 5th going up steep hills but what can I expect, 14000mi and a 2.3 with under 100 hp probably? Anyways, should I be concerned that the check engine light never came on with the O2 sensor unhooked??? Seems wierd to me.

 

So, it sounds like unplugging the sensor completely fixed it, right? If that is true, then I would replace it.

Does the CEL come on for a bulb check right after you key it on? If not, someone may have disabled it.

 

Blub is burt out!!!!!!!!! (shakes head) Replaced bulb (now it DOES work) and hooked everything back up to normal, unhooked battery for 30min. and wait to see if engine light comes on tonight and check codes tomarrow when it does. I will keep posting the results as I get them incase someone has simular problem, thanks!

 

Well, seems the EGR sensor was bad. Checked it and it had a bad spot plus the valve was stuck. After replacing the sensor and unsticking the valve it was clear of codes and ran fine. After I left I drove about 15 miles (light did come on about 1 mi. before) and check engine lights back on!! Before I got to my driveway it went back off? So, I talked to the mechanic I seen about it and there must be some carbon in there not letting the valve close completely and will probably have to be replaced. Computers!!!!

 

When the EGR is physically stuck open, it will be leaking at idle, too. That will cause a very poor idle or stalling. If you didn't have any idle issues, I doubt that the cause of the bucking was the EGR.

 

Well, it`s alot better! My mechanic is good with fords and he said that the EGR could be playing with the computer making it try to compinsate with something else, still needed fixed anyways. The temp is very low and it`s cold here in Iowa, 30F right now. He said too low of engine temp could cause bad milage and even make it run rich because the computer doesn`t think the motor is warm and keeps choking it. He recomended a 190F probably 160F in it now or possibly nothing at all! The needle is clear over on cold all the time and he used a temp gauge on the engine so the gauge is right.
U-joints went out yesterday, but that`s a whole nother story. This cheap truck is starting to kill me! $$$$$, thanks for all your help, really feel dumb about the bulb on the check engine light!

 

my guess is your temp sender is bad, i know mine was stuck on cold when it went bad.
as far as the no thermostat.. dont do it.. its in there for a reason..

 

No, I was saying there may not be one in there. Well there was but I replaced it with a 192F. Also, checked the codes again now O2 sensor with lean condition. So, the pc is pumping too much gas thinking its lean! Replaced O2 sensor and seemed to run good but then engine light came on again and shut back off, now have to see what code is popping up!!! It is running back rich again! Black soot on the ground when I start it. About to run this thing into a lake!!!!!! (bow head with fustration)