1994 Ford Ranger truck seems to miss a cylinder when idle

Tiny
KBHATIA007
  • 1994 FORD RANGER

Engine Mechanical problem
1994 Ford Ranger 6 cyl Two Wheel Drive Automatic 262000 miles

After a long dedicated 14 years, thhr ranger is beginning to act up. Have replaced fuel pump, fuel filter, spark plugs wires etc. But the engine seems to be missing firing on a cylinder when idling. When under power, it seems that the truck is going to buckle over and shudders very badly. The fuel pressure is good @45psi. The transmission has about 160000 on it. It was running ok till I decided to do some PM on it and has never been like before. Every mechanic has pointed in every different direction. The truck passed emissions with flying colors two weeks ago when the problem was intermittent. Now it is continuous. Compression in cylinder 3 is 75psi(as per the repair shop). What should I do next and what is the problem?
Thanks for your help.

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Wednesday, August 27th, 2008 AT 6:17 PM

23 Replies

Tiny
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260,000 miles is phenominal.

It may be time for a engine overhaul, sounds like the rings are wearing, how did a wet compression test handle? The pressure go up significantly?

75 is pretty low and will definetely make a missfire very noticble at low speeds.

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Wednesday, August 27th, 2008 AT 9:17 PM
Tiny
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Will be doing a wet test in a couple of days, but everybody wants me to swap the engine out, which I am very hesitant to do. Want to rebuild the head and the valves if that sounds like it will solve the problem. If the pressure comes up with the wet test then only I will swap the engine.(Indicating bad rings). We will know pretty soon.

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Thursday, August 28th, 2008 AT 7:19 AM
Tiny
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Rebuilding the heads as you suggest could work if the rings arent worn.

Might be time to checking the bearings also. The rings could be worn, the cylinders are probably worn.

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Thursday, August 28th, 2008 AT 2:20 PM
Tiny
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Thanks blackop555 :-))
We will know better tomorrow after the wet test. I think that will decide if I need to swap the engine of work the valves and the heads. I really do appreciate your input. Let us wait and seee.

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Thursday, August 28th, 2008 AT 6:59 PM
Tiny
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No problem, I hope the best cheapest way for you!

If you need further assistance im here to help!

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Thursday, August 28th, 2008 AT 8:51 PM
Tiny
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Hello blackop555:
This time did the compression test myself and found that all cyls had roughly 170psi after 5 piston strokes.
Too high but seems to me that the mechanic could be wrong. Now does that point to a clogged convertor? Two independent mechanics have already told me that there is metal coming out of the tail pipe. Truck drove smooth after I assembled the plugs back in the cylinder
really confused now.

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Saturday, August 30th, 2008 AT 1:39 AM
Tiny
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Hmm 170psi is a bit high, maybe a camshaft issue wouldnt worry as long as its runnign good now, could be that a spark plug wire was loose on the plug or damaged and when you were moving them around it made the wire complete connection again.

Would like you to check on that one cylinder momentarly see if when the engine runs rough if the compression drops back down.

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Saturday, August 30th, 2008 AT 9:00 AM
Tiny
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I realy appreciate you hanging in there for me and geting me through this, blackop555.
It is back to where we started. I will run over the truck to a muffler place to make sure the converter is not clogged. There are two holes on the side and I can feel the exhaust coming out of there. It has not run bad on idle and city driving like before, but definitely feels as if it is missing. The same vibrations on park and idle and same when the transmission is engaged with brakes on. The worst part is tat it is not displaying any codes. Says everything is good.

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Saturday, August 30th, 2008 AT 3:13 PM
Tiny
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Thats what im here for.

Chances all that would show up is a missfire code. But since pre obd2 didnt have missfire detection. It wont show up.

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Sunday, August 31st, 2008 AT 3:40 PM
Tiny
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Interesting observation. The truck has been running fine today(when it is a lot cooler here in Atlanta), but yesterday when it was hot, it acted up after running a few miles and being turned off in a parking lot. Hmm. What can it be?
There was no sign of a skip and the acceleration seemed normal. Idle rpm was higher. Is it a bad fuel pump out of the box? Not being able to keep the prime?. Or is it the ecm not geting fed back properly rom one of the sensors (the brake light does not come on when I engage the parking brake). Btw, in summer time in georgia, the ethanol content can go upto as high as 10%.
So here you go blackop555, does any of it make sense?
Thanks again

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Monday, September 1st, 2008 AT 7:20 PM
Tiny
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Uhh, check to see if the coolant temp sensor and intake air sensor are same temperature.

Mainly heat would be affecting the igniiton system not the fuel system such as the fuel pump.

Check the fuel pressure.

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Monday, September 1st, 2008 AT 9:36 PM
Tiny
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Hello Blackop555:
Did not act up yesterday, but checked the fuel pressure and was fine. Everyday when coming to work, it acts after it has been on the highway for about15-20 miles. Every time. The muffler people won't even do a diagnosis but want to change it out, citing it the miles on the truck as an excuse.
Don't know. Do you know a good mechanic in atlanta who can confidently tell me what is going on? At this time everyone want to take a shot on the dartboard and want o change everything out on the truck.

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Wednesday, September 3rd, 2008 AT 11:38 AM
Tiny
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No I wouldnt, what I would look for would be a individual ASE certified mechanic. Basically call around, describe it. See what they think and see if you an get a quote on it.

Lots of corporations like to go and do big things to make more money.

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Wednesday, September 3rd, 2008 AT 8:40 PM
Tiny
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Thanks blackop555 for your help. Finally took it to a ford dealer and the truck did not act up when they had it for two days. They are suspecting a fuel injector. So I am going to keep driving it till it acts up. I have a stethoscope with me in the truck so in case it does, will try to figure out which one.

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Sunday, September 7th, 2008 AT 6:45 PM
Tiny
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If your close enough you can take it to the dealership without turning it off and have them go for a spin!

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Monday, September 8th, 2008 AT 6:10 PM
Tiny
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Hello its me again.
Had it going fine for 10 days or so, and then it acted up again. This time when I unplugged the ignition wire from the coil for #3 there was no change in th erpm, when I plugged it back, the engine was back to normal. The injectors were all working with a nice even clicking.
Do I need to change the coil pack? Do we need to reprogram he ECM? What would you do?

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Saturday, September 20th, 2008 AT 11:10 AM
Tiny
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If the coil is bad it could cause the injectors to act up and the spark.

I would try a cheap one that works and see if it remedies, its worth a try.

Second you unconnected and reatached it ran good/ you remove engine running or off?

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Saturday, September 20th, 2008 AT 4:35 PM
Tiny
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Thanks blackop555 for your reply.
The engine was running. When I removed the ignition wire, I could see the sparks from the coil to the wire boot, which in turn tells me that the coil was ok?
The wire sets in use are non-ford parts (the spark plugs are oem motorcraft from the dealer). I have already changed two sets of wires with the same result. Do you think that I should just buy the wire set from the ford dealer also? Also go ahead, spend the money and buy a new coil from ford? Or is it something else that needs to be explored.

This is so confusing.

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Saturday, September 20th, 2008 AT 10:44 PM
Tiny
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Measure the resistance of the plug wires, should be no more then 10,000 ohms per foot of the wire.

The coil, I would go with a cheap coil and if it clears up then chances are that was the problem, some aftermarket work just as good as oem.

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Monday, September 22nd, 2008 AT 9:20 PM
Tiny
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Hello:
The wire set in use had an average resistance of about 6K/ft. Replaced them with the other set that was about 2K/ft. So let us see the difference. Tomorrow if it is not better than will go out and buy oem plug wires and then the coil. Guess all three need to like each other. Ha. Ha. Ha.

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Tuesday, September 23rd, 2008 AT 6:42 PM

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