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1993 Ford Ranger - Sputters and lurches

1993 Ford Ranger sputtering issues
truck lurches, can’t accelerate, greatly reduced power, chokes and burbs when trying to accelerate or even idle too long
replaced fuel filter, treated fuel, replaced MAF Sensor, cleaned out catalytic converter, tested with muffler pipe off in case it was muffler … but alas no answers yet
my mechanic, the sound board guy from Raleigh Vineyard who is a mechanic in real life and has a lift at his house is stumped
if you step on gas pedal (or push accelerator with hood open) … more than one third the truck chokes and sputters … if only go to about one third it moves forward steady (obviously can’t really drive like that, can’t accelerate on left turns in traffic)
any ideas?

Is the check engine light on? Does your sound man/mechanic have a code reader for this OBD1 truck? What are the codes?

If he can’t read these codes, I suggest you find a mechanic that can. Yours seems to be wandering in the dark and burning your money for light.

Has he checked the fuel pressure? This sounds like a fuel problem. Pressure regulator, fuel pump, injectors, somewhere in there.

Check engine light was on, but related to the MAF.
Fuel pressure is strong, he has tested it several times and believes it is not the fuel pump as a result.
did not replace fuel injectors but treated a few times with additive.
will ask him about pressure regulator.

{My Mechanic updated
saying he also replaced Plugs, caps, rotor and wires. Plugs Motorcraft. Ford OE. Fuel pressure at
spec (34-38 psi. Code was for MAF sensor

{My Mechanic also re-wired the maf sensor saying it was
running too rich and someone had miswired it and that’s probably why there was
so much junk in the catalytic convertor, the MAF-S would have been re-wired by
a home mechanic way back in 2007. The
truck has gone long periods of not being driven while I was overseas, as little
as 30 miles in 3-6 months. However I had
driven the truck several times in Nov-Dec 2018 after 4 months away, but before
the problem came suddenly around Feb 2019}

There are 4 different MAF codes for a Ford. They all mean different things and require different repairs. Is the light still on?

I’d guess the injectors are buggered up with stale fuel.

Not sure why anyone would “rewire” a MAF to richen the mixture. In any event, you need to un-modify any other of the previous owner’s shadetree hack jobs.

It wasn’t the previous owner, I knew them and have all paperwork, but it was a home mechanic thru a freind (not the real mechanic freind I have now) … and it ran fine since 2007, but yes sir, my new mech has rewired it back to spec
I have treated the gas with injection cleaner, but are you saying (and I am not a car guy) the the injectors need replaced or can they be taken off and cleaned or whats the process for that?

“online says” either I need special fuel injector cleaner machine or have to take the upper intake manifold off (not something i can do and sounds like a big job) but does this sound right … and should I just replace them if doing all that work? ($50-65 online)


Well, 26 year old injectors with a dodgey past… For $60, I’d replace them, especially if you have to pull the upper manifold off to get them out. They can be cleaned with a special machine but the cost is likely more than new.

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ok thank you, will keep plugging away (pun intended) until its running well. Truck has new tires and brake calipher so worth it to me to keep going, a few hundred is in my budget $5k for new used is not. So thanks for your help.

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If this truck has antique gasoline in it then it needs to all come out. At some point there is no treatment for very aged gasoline.

The engine also has a MAP sensor.

A bad MAP sensor can cause this problem.


thanks we will look for that

Those EEC systems could be a real pain without a good scan tool and a breakout box. Even then they were still a pain. It might be worth it to find an old mechanic with a Snap-On scanner and some experience on old models. Seems like I recall reading 6 lines of live data on those old Fords with freeze frame to catch glitches. I’m real surprised it wasn’t low fuel pressure.

Your mechanic cleaned out the catalytic converter? How exactly was that accomplished? Given the symptoms my first guess is the cat is plugged and not freely passing exhaust gasses. You might try removing the O2 sensor and try running the engine (at idle and slow rpm) that way. If that makes a big performance improvement, pretty clear clue the cat is clogged and needs replacing. (This will make a lot of noise!)

Beyond that – besided properly reading out all the diagnostic codes and following the related procedures – test for the fuel pressure, intake manifold vacuum, ignition system, and cylinder compression should be considered.

thanks for responses, gas is almost all drained, we are gonna try using pressurized fuel injector cleaner on Sunday afternoon.

but to George specifically, the CAT is cleaned, simply take it off and clean it out, I have pictures, but just because you don’t get what he did, doesn’t mean he didn’t do it, I’m on here cause we hit a “wall” but please be civil or don’t respond, I’m sure everyone would agree (sarcasm, like car talk is known for, is a good humerous thing unless it’s used in a demeaning way)

George is not being demeaning. Cats don’t get cleaned. They are not filters. If they clog, it is usually because they have melted down internally. No cleaning is gonna fix that.

If they throw a code on an OBD 2 vehicle some people think laquer thinner will “clean” them. It might get you through one more inspection but they will reset the code soon enough.

I had the same question but an OBD 1 car would not matter either way. If it was clogged from a meltdown, it could not be cleaned. If it wasn’t clogged, cleaning would neither help nor hurt it.


Please no more responses on the CAT, it was clogged, it was cleaned, I have pictures, I trust my friend who did it and who is a professional mechanic for 30 years, it is a finished subject, thank you

Codes only showed bad MAF, as per prior discussions MAF was replaced.
Will ask and or we’ll check on the other suggestions tomorrow when we clean the injectors.
thank you.

any chance your alternator is going bad and you are losing voltage at higher rpm?

If you haven’t looked into the Ignition control module, that would be my number one go to with the issues you are having.

99% sure your ICM is bad.

We must be getting a bad reputation here fellow Car Talk Curmudgeons. Maybe Miss Carolyn can post a header warning the thin skinned to enter at their own risk.

But to be immediately understood on what was done you might want to describe that your mechanic’s procedure “gutted” the cat, @Mrjeff1. I can assure you that a great many mechanics have done that over the years And that subject will continue to be haggled contentiously here until the lights are turned off.