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2003 Ford Ranger. About 175,000 miles. Automatic 3.0.
It accelerates slowly from about 50 or 55 up to about 65 and then it really struggles to go any faster. It speeds up a bit then slows then speed up again, but stays right in the 60 - 65 range over time, it will accelerate over 65 but it really struggles. It shudders and bounces in the 65- 70 range, but above 70 it seems to do better, but it will not stay above 70. The check engine light flashes on and off and then goes off when I drop below 65. The tach does not jump around or anything so it does not appear to be jumping between gears. The way it acts is similar to when I have redlined cars with safety features to keep you out of redline, but it is at about 3500 RPM at 65 MPH. At lower speeds it does OK, but sometimes the acceleration is doggy.
Check engine light was on earlier and it said misfire in number 4 cylinder. Replaced the spark plug wires and the check engine light went off and it seemed to run better for two days (except not at freeway speeds - it still had the problem in the 60-65 MPH range). Yesterday the check engine light came back on and it struggles to accelerate at lower speeds sometimes (like it did before replacing the spark plug wires).
I suspect a transmission problem, but it did not read transmission problem on the code reader at Auto Zone. The only code was the misfire in cylinder 4.
Transmission fluid does not go down, the oil stays up (except or a small valve cover leak) and the coolant is clean and steady. No bubbles in the coolant when the radiator is open. It does have an exhaust leak we tried to get that fixed and they could not find it. I can hear it, but cannot identify which cylinder it is from or where it is when the truck is running.
We will probably try to figure out the problem this weekend. Any suggestions are welcome.
Has regular suggested factory maintenance been done?
That is in the back of your owner's manual and in the factory service manual, it will list things which should be replaced at various mileage intervals.
If that has not been done, I would replace filters - oil, air, fuel.
Change oil.
Replace O2 sensor.
Replace distributor cap and rotor if you have that.
Replace spark plugs and be DARN sure the spark plugs and spark plug wires are factory specification and not some fancy "upgrade" (which can cause problems).
Then replace the Throttle Position Sensor - just because! (I replaced mine on a truck with 200k miles and took apart the old one. It was badly worn and because of that it was not making good electrical contact in some positions - it is based on that sensor's readings that the engine computer gives the engine more or less fuel. Good to have that giving accurate throttle position information to say the least!)
Generally just doing the above will do wonders for a vehicle which has not had regular service.
Then with high mileage, check all the vacuum lines for vacuum leaks. This is the black rubber vacuum lines or portions of vacuum lines. Look for hard or cracked lines [black rubber]. Replace with new flexible snug fitting lines. (You can buy that by the foot at an auto parts store.) Note: The tiny hard plastic light colored vacuum lines are usually ok.
Then for your specific problem above, if still having the same problem after doing the above and replacing the fuel filter, also do a Fuel Pressure and Fuel Volume test (flow). The fuel line needs to have a certain pressure, but also it needs to maintain that pressure as fuel is being used. It needs to be able to supply a certain quantity of fuel as the engine goes faster and needs more fuel. But if the fuel line is blocked, like with a clogged fuel filter, then you will get high pressure at idle, then it drops when the engine needs to use more fuel (the "flow" or "volume" is not there).
Beyond that, if you are still having problems, use the factory service manual for troubleshooting.
With that many miles, and not knowing how well it's been maintained, there a lot to suspect. I think the 3.0 is a timing chain engine, so i don't think the timing has slipped. The first questions I'd ask are if routine maintainence like spark plugs, fuel filter, etc has been done. I'd probably pull spark plug #4 and see how it looks. Is the electrode brown (normal) or white (running lean).
Usually with these symptoms i'd suspect running lean (struggle to supply fuel) or even a clogged cat converter.
Do you have the abilty to read codes at will, or must you run to Autozone? A good OBD2 code reader can be had relatively cheap
Don't go changing a bunch of parts "just because." What if you spend $300 throwing parts at it and it still doesn't solve the problem? If it turns out that it needs a major repair that you're not interested in investing in then all that money will have been wasted.
That YM Ranger 3.0 was subject to bad coil packs and burnt exhaust valves. I'd check the cat to see if it has issues first followed by a tune up unless you know all of the ignition parts are fine. Do the cheap stuff first but the valves are the most likely issue with that many miles. If you have a compression gauge.......
I'd have engine and transmission replaced. Maybe half of electronics also. Just for the heck of it.
Just kidding.
It's Ranger. Those are super reliable. What you have is very likely simple tune up and maintenance issue.
First thing you do is to take car to any parts store and read error codes. Start from there.
While at the store, you spend $14 to buy repair manual.
Then you either repair what codes showed, or maybe take truck to a decent private shop for full diagnostic and then DIY repairs. It's much better spent $70 than tossing parts at it.
I'd also start with flushing system with Seafoam, two tanks in a row, two cans, one can per tankful.
Otherwise, it sounds like an air leak somewhere, as in - vacuum leak. Turn engine on and give short bursts of brake cleaner via straw, aiming at different engine areas with gaskets and throttle body. If it bucks, you have it.
AIr filter. Fuel filter is most likely due. EGR valve needs to be cleaned. Got some mileage.
That YM Ranger 3.0 was subject to bad coil packs and burnt exhaust valves. I'd check the cat to see if it has issues first followed by a tune up unless you know all of the ignition parts are fine. Do the cheap stuff first but the valves are the most likely issue with that many miles. If you have a compression gauge.......
It is not Coil on plug. Spark plugs are 11 months old platinum m and clean. Wires are 2 days old. The prior set was 11 months old.
Don't go changing a bunch of parts "just because." What if you spend $300 throwing parts at it and it still doesn't solve the problem? If it turns out that it needs a major repair that you're not interested in investing in then all that money will have been wasted.
Yup. I am not going to put a bunch of money in a 175000 mile truck that may have a bad transmission. I will fix what is broken.
With that many miles, and not knowing how well it's been maintained, there a lot to suspect. I think the 3.0 is a timing chain engine, so i don't think the timing has slipped. The first questions I'd ask are if routine maintainence like spark plugs, fuel filter, etc has been done. I'd probably pull spark plug #4 and see how it looks. Is the electrode brown (normal) or white (running lean).
Usually with these symptoms i'd suspect running lean (struggle to supply fuel) or even a clogged cat converter.
Do you have the abilty to read codes at will, or must you run to Autozone? A good OBD2 code reader can be had relatively cheap
I wouldn't suspect transmission here just yet, but would suspect a dying fuel pump perhaps, or a clogged fuel filter.
Do not have a code reader. One available at harbor Freight for 4100 ($50 on sale) was recommended. It reads a lot of things only the more expensive readers read. (Like ABS). I will look at the Amazon one thanks. I was told with that brand, you are paying more for the brand name, but it is cheaper on Amazon.
Maintenance is pretty good regular oil changes, filter, air filter, lube, spark plugs and wires. Pretty much everything else gets fixed if it fails.
When the cat clogged on our van, it was just like it a constipation all the time, It was not something that kicked in only at high speeds. I can rev it to 3500 rpm at lower speeds and not have a problem, it only occurs at 60-65. Except the acceleration is doggy sometimes. It does ok coming out of a light, but accelerating to freeway speeds it is slow to accelerate, but it does not buck and jerk until 60-65.
I will have the cats checked. I do not know how to test them myself. Maybe my son knows.
I will just replace the fuel filter. That has not been done since we got the truck (about 20K to 30K miles). I will check with Dad first and see if/when he did it (we bought it from him).
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