Have a 94 ford ranger XLT 4.0lL Extended Cab. Having rough idle and occasional stalling. Usually at idol but lately is happening at driving speed also. Used to run perfect. Then one day CEL comes on and it starts running rough and trying to stall like something is clogging the fuel. Then while driving would jerk like it had cleared the fuel line andl light would go out and run perfect again. Couldn't figure what was causing this. Changed Oil, plugs, Fuel filter was changed and injectors cleaned by shop and a new fuel filter. last year but does not have but 5000 miles since installed. As time passed the light staying on became longer and times it ran perfect where shorter. Now Light stays on all the time. Have to drive with 2 feet. Always started without problems. Now I am getting occasional back fire and Black inside tail pipe. Is it possible for the ICA to be the culprit. Could it clog and unclog and clog and unclog till it stays that way or when it clogs once it stays that way. Or perhaps a loose or corroded electrical connector, Clogged exhaust system? PCM was replaced about 6 months before these issues started a year ago. So I don't believe this to be the issue. My OBD1 is broken so I have no codes yet. Need to get a new one on payday. I have no formal automotive training. I have an IQ of 147, Usually very good at figuring out problems and fixing them on almost anything. Computers, laptops, video game consoles, Arcade Game Machines, slot machines, tv's, Furnaces, Home A/C units, Etc. etc. I am self taught in everything. But this is driving me up a wall. Cannot figure what would cause it to run perfect then messed up then perfect. Any one that can help me on this I can help you with advice on fixing some of the above mentioned items. Thanks in advance to anyone that can help.

 

Welcome to the forum

Try to break up your paragraph for easier reading

You need to read the Codes in memory, very easy to do, watch this video: www.youtube.com/watch?v=X07hu0kAuzE

1994 will use 3 digit codes

List is here: http://www.therangerstation.com/how-...3-digit-codes/

Fuel pump circuit code could mean fuel pump relay is starting to fail.

You could have partially clog exhaust, Cat or muffler has rusted out and parts are shifting around inside, so good flow/bad flow

On the top side of the engine behind alternator is the Fuel Pressure Regulator(FPR)
It will have the Fuel Return Line attached, and a Vacuum hose
FPR diaphragm can leak, and raw gasoline will be sucked into the engine via that vacuum hose, causing Rich running and poor running.
Check that Vacuum hose for gasoline, if found replace FPR

IAC(idle air control) Valve can cause poor idle but not poor running, but it is easy to clean: How to: - IAC valve cleaning thread (w/pics) | Ford Explorer and Ford Ranger Forums - Serious Explorations

Fuel filter is about $10 and should be changed every 5 years or so, or if you don't know when it was last changed.

Clean MAF sensor, once a year, but at least every 2 years, need a low residue spray cleaner, again not hard to do.

Run a can of injector cleaner in gas tank once a year

 

Sorry about the huge block of text and thanks for the response.

Since all this started I have been running injector cleaner, octane booster and fuel system treatments alternating between them each fill up.

Have found no fuel in the in vacuum lines.

After reading a few threads yesterday I cleaned the IAC and the mass air flow.

My little ranger is growling again. It has its horsepower back now. It no longer wants to stall while driving or at lights.

No more two feet driving. Yeah!

I drove around the block several times hoping that the CEL would go out. but no luck.

Later when my wife got home from work we went for a drive. I let here drive.

5 seconds out the drive way it went out. we stop at the store and when we were leaving I decided to drive.

Upon starting the CEL light came back on. It was a short trip home and pulled into drive way which has a somewhat steep downward sloop.

In the driveway I let it run about 8 min later it stalled. I am thinking that the IAC being clogged so long has fouled up everything from running to rich over the past year.

I figured that was the issue when I first seen the black residue in the exhaust pipe. Just couldn't find the issue.

Now that that issue has been resolved. I believe the motor, exhaust and/or muffler is probably gunked up. (No CC on this one, Previous owner removed it)

Will running the above mentioned additives clean this up since it is no longer running rich from normal operation or is there some thing I need to do.

Thanks to all for posting their issues those threads helped a lot.
Chris

 

Just watched the you tube video you recommended.

I am going to try and pull some codes.

Also saw a video for sea foam. Was wondering if anyone thinks that might help clean up any exhaust build up that has accumulated in the last year.

Next post should have the codes.
Thanks
Chris

 

No on the Seafoam, except in the gas tank
4.0l is not know for carbon build up, and engines will start to "ping/knock" when accelerating when that happens.
Exhaust system itself can not be cleaned, just parts replaced

Clogged exhaust is first noticed as lack of top end power, exhaust pressure builds up so no new air can come in and you reach a power limit, an RPM limit
A piston engine is just a self powered Air Pump, so if you restrict Air IN or Air OUT, you restrict pumping power
Thats why a "potato up the tail pipe" can cause stall or no start, lol.

Only vacuum line that can get gasoline inside is the FPR's vacuum hose, so thats the one that you need to remove and check, very common issue

 

Here are the engine off codes I got 181 167 157
Here are the on engine codes 116 172 536 (536 came as I had foot on brake.)
I did not warm engine first. I was low on radiator fluid which is why 116 came up. I topped that off.

Seems it was running lean not rich. (Kind of surprised me. Thought it would be the other way around as mileage has been crappy.)
I wiped the codes after and drove around the block to warm engine. As soon as I pulled out of the drive way CEL light went off.

After engine was warm I pulled back into driveway and tested it again.

Only code I recieved was 111 which is fricken awesome. Seems the whole problem was the IAC and MAF needed cleaning. If I have any more issues with it running lean I will just replace the IAC as it might be sticking again.
Thanks ROND that code reader trick makes working on the truck so much easier. God Bless you! (and I not that religious lol!)

Chris

 

Will be coming back here again to see if I can help others as others and you helped me.

Chris

 

Good work

Thanks for posting the update

O2 sensors use a chemical reaction and they do run out of chemicals, they usually last 100-125k miles
As the chemicals run out the O2 tells the computer the exhaust is Lean, when it is not, so computer adds more fuel than needed and MPG goes down

O2 sensors are not all that expensive, so worthwhile to change them to get best MPG which will actually pay for the new O2s over the next 100k miles

 

Great Advice. My little ranger is at 129956 Miles and used to get awesome mileage for the trucks age.

Will definitely be working on that soon.

Do they all need to be replaced at once or can you do it one at a time. As I am still waiting for my tax return.

Chris

 

1990-1994 4.0l Ranger will have two O2s one for each bank of the engine
1995 and up had 3 sometimes 4

You can replace them one at a time, up to you, won't see much of an MPG change until both are changed

O2s have a universal connector, so can be plugged into either side of a vehicles wiring harness
The truck wiring harness has a Passenger side and Drivers side O2 plug in, and you should never mix them up, there is one wire difference, in case you do, but just do NOT unplug BOTH at the same time, so you can't mix them up.

Had a shop do that to one of my vehicles, not sure if it was an "honest" mistake or on purpose.
Picked the vehicle up and all was well, after a few minutes it was running like crap, and CEL popped on, had own the vehicle for 10 years and never had a CEL
Called the shop and they wanted me to bring it back in.
Said yes but decided to have a look myself
Codes were lean on bank 1, rich on bank 2 ???
Engine ran fine cold only started to run poorly after a few minute warm up
Also even when running poorly if I floored it(wide open throttle) it ran perfect again until I let off the gas pedal, and that gave me the clue.

O2 sensors need to be 600+ degF to work, so computer ignores them on cold start
O2 sensors are also ignored at WOT(wide open throttle) since POWER not MPG is the main point of WOT.

So checked O2 wiring and sure enough wires were reversed, switched them back and no CEL and back to running great

Called the shop and told what the problem was, they said it wasn't anything they did and that wasn't the problem in any case and I should bring it in again, so the "honest" mistake thing popped into my head as a maybe not, lol.

 

Yeah, seen some real dishonest mechanics before. lol. Hard to find a trust worthy one.

But when you do its a great feeling.

Went to a couple of places Cel came on for a few seconds then stayed off even after restarting.

Seems that it still tends to stick a little when cold. Couldn't get all the build up off the plunger.

Thinking about getting some part cleaner and putting it in a bowl and leaving the part in it over night to get the rest of gunk off the plunger.

And if that doesn't do it I'll replace it.

Thanks again
Chris