1993 Ford Ranger 2wd 4.0 Auto
I bought the truck this way and I cannot figure it out. The truck starts right up and runs fine. If I smash the pedal to the floor in drive or neutral the motor misses and bogs. If i ease into it it revs up just fine. I checked fuel pressure. Idling is about 32 psi and at WOT it is about 40. I changed the plugs they were all white. Changed wires and threw a used coil pack i had in the garage in it and no change. Changed the fuel filter. Truck sat for 3 years and my buddy bought it. Would not go over 50. He did a tuneup on it and drove it for 6 months the way I am describing. Other info I can tell you is the truck does not like to heat up. I changed the thermostat and still it barely gets off the line if your driving it and maybe an 1/8 of the way up the guage, just sitting. No check engine light currently but it you drive it on the freeway above 50 it will come on and go off when you reach cruising speed. Please help I have been tinkering with it for days. By the way I'm new to forum and like what i see.

 

Run the codes and that will probably tell you what your problem is...

 

I cant I dont have and OBD1 scanner and i tried the key thing but I dont think it is storing the codes.

 

Aside from the misfiring, it sounds a bit like you may have a clogged catalytic converter. It blocks the exhaust and the further you lean into the throttle the slower it will go.

Does the problem get worse as the truck gets hot?


I've had this problem on several GM vehicles, I suppose ford could have the same problems.

 

I'd Seafoam it since it sat for so long.

 

I seafoamed it and i cut the cat off already. Alright after some research on obd1 codes. I got these. 111 157 122 158 181 185 186 189.

 

My gut keeps telling me the injectors aren't firing right. Do you have any Lucas Oil's Fuel Cleaner you can run through a tank....really good stuff.

 

I ran techron through it already but Im willing to try anything.

 

I've seen engines totally rejuvenated with the stuff...available at lotsa places. It may not fix your problem, but I won't hurt.
Lucas Fuel Treatment : Lucas Oil

 

i think you mean eec IV, not ODB1... the codes mean:

111: all systems ok

157: low voltage MAF

122: low voltage TPS

158: high voltage MAF

181: fuel system rich, partial throttle

185: below spec manifold airflow sensor

186: too long injection time pulse width

189: Lambda sensor on left, mixture too rich (part throttle)

sounds like you have a lot of contradicting codes... here's what i recommend you do... clear all codes, see if that makes a difference in the overall vehicle performance, i did this on my mustang, and it cleared up a good few problems, car ran better, got better mileage... AND the next time i checked it (week later) i didn't have 5-10 year old codes in the memory...

maf voltage high AND low, doesn't make sense to both be there... clear them all, both KOER and KOEO codes

next time you check them, it should give you 2 sets of codes, it will give you both twice, so it will be like beep---beep---beep----------beep---beep-beep---beep-beep---------beep---beep---beep----------beep---beep-beep---beep-beep---------------beep---------------beep---beep---beep----------beep-beep---beep---beep---------beep---beep---beep----------beep-beep---beep---beep---------

which would be 111, 122, 111, 122, (long pause)1(long pause), 111, 211, 111, 211

the first set (111,122,111,122) means that you have 2 codes, 111, and 122, it just repeats it, so you can make sure it's written down properly, there is a long pause 1 beep and another long pause, this is a seperator beep/flash, and a second set of codes (111,211,111,211) which would be codes 111 and 211... i forget which is which, but i believe one set is what is in the memory, and the other one is current readings you can do the codes with the engine off, and then again with the engine running, for a total of 4 sets of codes... if my memory serves me correctly, but it's been about 2 years since i ran a set of eec iv codes... if you really want me to, i can go upstairs and see if i can dig out my eec-iv diagnostic book

 

let me clear them in the morning and drive it and see what i get. Thanks.

 

you are always better off clearing your codes, after you are sure you have them written down, if it was a 1 time error, the computer may still be compensating for it... if it was not a 1 time deal, the code will be set again... i would say drive it nicely, check the codes, take it on the hiway, nicely, check the codes, give it WOT in neutral AND drive, check the codes, (clearing after all of them) do all of the above, check the codes...

i would probably do the last, first... to see if any of them will set a code...

TPS voltage is SIMPLE to check, AND set it takes 2 sewing needles, 2 wire jumpers with aligator clips, a philips screwdriver, a volt meter and sometimes a drill bit or a round file...

i don't know the wires which is which, but you put 1 sewing needle each into 2 of the wires coming out of the TPS, hook the aligator clips to that and the leads on the volt meter (the aligator clips just make it easier, as you don't need to hold it) loosen off the philips screws holding the TPS on, just a little, turn the ignition ON engine off) and turn the TPS till you reach the proper voltage, i don't know what it is on a ranger, i think my mustang's was .98 v. when the voltage is set, carefully tighten up the screws holding the TPS on, making sure not to change the voltage being read...

from here, you should test the TPS, slowly open the throttle (by hand, using the throttle linkage on the other side of the TB) all the way open, and all the way back closed, looking for any abnormalities in the voltage, it should be a smooth increase in voltage all the way to WOT, if there are any jumps, or flat spots, your TPS is pooched, toss it and buy a new one...

this actually sounds like it might be the problem, a flat spot in the 1/2-3/4 range, or higher, which causes the computer to stop sending fuel to the motor (as it thinks the throttle is closed)