Lack of power

I recently finished body work on a 2000 ford ranger 4wd. I was fixing it for my sister and it had been wrecked into a tree. Anyways, it has 118000 miles on it. It is the flex fuel engine. I did a trans service and oil change and it runs absolutely great. No misfires, no check engine light...nothing. However, this thing is so doggish. If I hit a little hill, it bogs it down and it has to downshift. I know these things are no powerhouse, but I own 2 of these myself. 1 though is geared down for big tires and the other is a non flex with a standard trans, and they both scream down the road compared to this one.. Is it normal for these trucks to be so sluggish? I am going to pull a couple of plugs tommorow to see if maybe it just needs a good tune up. Anyways, I guess my only issue is lack of power. Is it normal for these trucks stock with auto transmissions to be so sluggish?

No, not like you describe.

Check compression, 3.0l should be 165+ psi

2000-2001 3.0l was rated at highest torque for any year Ranger 3.0l, 190ft/lb, other years were 180ft/lb, and 150HP.

Also check CKP(crank position) sensor, next to crank's pulley, it if was moved a bit, in collision, then spark timing would be off so lack of power.

Make sure air flow IN is not restricted, and Exhaust OUT is not restricted.
Check Cold Air intake tube in rad support and make sure the air pre-heater flap is not restricting air flow IN, run it without air cleaner top and filter if not sure.

Hook up a vacuum gauge, 18"-21" is expected at idle, low compression = low vacuum, just FYI
Open throttle all the way then let it snap closed, vacuum should drop to 0"-2" at WOT then pop back up to 18" immediately when throttle is closed, if it slowly comes back up to 18" then exhaust is blocked.

Collisions can shake loose alot of stuff, including the guts of Cat converters and mufflers



Do a roll test to make sure nothing is dragging, flat ground, engine idling......get out and push it

Re

Hey Ron, yeah, I thought it should have more power, based on my other trucks. I just was at a loss since the check engine light is off. I never thought to check the crank sensor out. I also will check out vacuum and the exhaust. I just figured the O2 sensors would be going crazy if the exhaust or vacuum had issues, but I suppose it might not and I sure don't know as much as you do, but I'm learning. It really does purr like a kitten though. I thought about a brake dragging or something, but it rolls freely. I also thought that maybe it is the transmission. I heard a metal on metal sound down around the torque convertor area when I first fired it up, but it only lasted a short time and then disappeared completely. I was worried that maybe the trans got jammed up somehow in the wreck, but it would have busted the bellhousing if that happened...wouldn't it? It shifts beautifully though. I don't even feel it shift. I wouldn't even know it shifted, if I didn't watch my rpms. That though is another thing, it is shifting at 3000 rpms if I give it half throttle. That seemed a bit high to me. I haven't mashed it to the floor or nothing though. I don't feel like working on it more because of my stupidity. lol

The computer monitors its systems, if there was too much fuel or too little then you would get a CEL.
MAF sensor tells computer how much air is coming in so it can calculate the amount of fuel to add, but it can't tell if there is a restriction pre-MAF that is limiting air flow.
Same with O2s, if there is the correct amount of oxygen in the exhaust then as far as computer is concerned all is well.
If exhaust has limited flow above 1,500-2,000 RPM then back pressure builds up which causes less new air/fuel mix to come in on intake stroke(and less air pulled in at MAF sensor), so less power but the the O2 still shows "good" burn, because the air/fuel that did make it in was correct 14.7:1 ratio, so no CEL

Engines are air pumps so a vacuum gauge can tell you alot about it's condition.

You also loose the negative pressure in exhaust system at mid-RPM range even with a small restriction on exhaust.
Rangers have a tuned exhaust system, at the mid-RPM range the tune causes a lower pressure at exhaust valve ports, this pulls exhaust out of the cylinders when exhaust valves open, so the piston and crank loose less energy pushing it out.
This is called a Scavenging exhaust system.

Most after market headers are tuned for low RPM range, so create the lower pressure at the exhaust valve ports sooner in the RPM range giving engine more low end power, you do lose mid-range with this.
And there are Racing headers that create this lower pressure at high RPM range.

Factory tuned exhausts are where the Myth of engines needing back pressure comes from.
People removed the factory exhaust manifolds and installed "free-flow" manifolds, larger pipes, then go for a test drive.
"Hey, WTF, I lost power!!", "This engine must need back pressure"

The result was correct, you would lose power, but the conclusion of why is not correct.
The smaller factory pipes created the velocity in the exhaust manifold system that creates the lower pressure in a specific RPM range, when they put on larger pipes at the heads they lost that velocity and so lost the Scavenged power it provided.
No 4-stroke engine runs better with back pressure


Any part with a large enough mass/weight can be damaged in a sudden stop, torque converter full of fluid is pretty heavy, but I think you would notice it slipping, if RPMs climbed up but speed was slow to respond, like a clutch slipping in a manual trans.
Now the torque converter is against the crank which also has some weight to it, and the crank is held in place by thrust bearings, length wise.
Torque converter is not 'attached' to the trans, it slides in and out on the input shaft.
A sudden stop while engine is running could damage thrust bearings, big maybe on that though, only way to tell is to check end play on the crank.
I don't think it could bend the flexplate because torque converter is pressed against crank in the center

Re

Alright Ron, thanks for the information. That makes sense. I didn't know that at all about exhaust, and was actually one of those people who believed the backpressure myth. lol. I'm going to have to borrow some guages from the parts store, but soon as I do, I'll start testing stuff. I also was thinking about the exhaust test....since I don't have a guage, could I just take out the O2 sensor and drive it a short distance to see if it runs better? I know it will show a code doing that, but wouldn't it tell you if the exhaust was plugged up? Anyways, that's was just a thought.

Depends on where both upstream O2 sensors are.

Exhaust is very very hot and can melt wiring pretty fast, so if O2 hole is pointed at wires............

Vacuum gauge costs $20 and is a good tool to have in the tool box.
No matter how many electronic gizmos "they" add, any gas engine is still just an air pump so vacuum will tell you alot.

Good read here on vacuum testing: http://www.gregsengine.com/using-a-vacuum-gauge.html

Update

Well, I checked the crank sensor to see if it was damaged or moved in the wreck. It looked perfect. I also pulled every plug and checked the gap, and the plugs looked brand new. So, I'm good there. I also took loose the inspection plate on the transmission and I could see the back of the flex plate and there was no obvious problem and with it running, I didn't notice the crank walking in and out any or nothing. I also checked the air box for a restriction in front of the MAF sensor by taking out the filter from air box and inspecting the piece that goes through the core support. I didn't notice a blockage, but it was hard to tell without taking out the headlight. I let it run with the top off the airbox and didn't notice much change....of course I didn't drive it to much that way. I didn't do the O2 sensor thing though and will probably do like you said and just go buy a guage. My sister took the truck today though and I told her I wanted to do some more testing, but she needed it and I don't know when I'll get my hands back on it, but when I do, I'll tell you the outcome of the vacuum test. Also, I put a piece of hose to my ear and listened to the bottom of the bell housing and I did hear a faint tapping noise. I am probably just hunting problems though and it wasn't nothing. It may have been the exhaust or something tapping against it. Anyways, I'll let you know the vacuum test later. Thanks for all your help and advice Ron, I appreciate it.

I have the vacuum readings....

Hey Ron, or whoever else reads this, I have the vacuum readings today. I hooked my guage into the brake booster port on the upper intake....it was the easiest place to get to. I started the engine up at operating temperature and the gauge was jumping randomly between 17 and 18. Then I opened the throttle and released it fast and it went to 0 and rapidly jumped up to 23ish or maybe a little higher....it happened fast. It hovered around 23 and then dropped back to 19/20. It was randomly jumping a number. It wasn't a consistent jump though....like it would stay on 19 for a couple seconds and then jump to 20 for a couple seconds and so on. At that point I shut it off. According to the info that Ron posted above, that means it is in good shape...right?

Edit: I read Ron's info again and it said if it drops to 0 and then back to 22, then it was worn rings. Anyways, it isn't burning or loosing oil though, but maybe the rings are bad causing a lack or power? I don't know. It only has 118000 though, so I wouldn't figure it would have bad rings...especially since it isn't loosing oil. Also, it said with worn rings that it would have a lower than normal reading at an idle...which it didn't.

I just did a quick read of Ron's link. According to it you may have ignition problems. Go back and read it again.

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alwaysFlOoReD said:

I just did a quick read of Ron's link. According to it you may have ignition problems. Go back and read it again.

Click to expand...

Possibly...it kinda sounded like incorrect spark plug gap, but I checked the gap and it was good. It said between 14 and 16 indicated a ignition problem. I never had a reading that low, but 17 was close to it. It also might be an ignition problem due to the slow jump and fall of the needle. The more I read info, the more confused I get. What else would cause an ignition problem on it? Maybe the cam sensor or bad syncros? However, it would probably have a code show up from that....wouldn't it?

This is what I was talking about in the link;

With the engine idling, continued fluctuation of 1 to 2 inches may indicate an ignition problem. Check the spark plugs, spark plug gap, primary ignition circuit, high tension cables, distributor cap or ignition coil.

Click to expand...

And you said this;

I started the engine up at operating temperature and the gauge was jumping randomly between 17 and 18.

Click to expand...

and this;

It was randomly jumping a number. It wasn't a consistent jump though....like it would stay on 19 for a couple seconds and then jump to 20 for a couple seconds and so on.

Click to expand...

So that is why I suggested ignition problems.

Vacuum level at idle should be steady, if it is jumping up and down, even 1", then there is a misfire, and as one cylinder misfires one of the other cylinders will be on it's intake stroke and crank slows down during the misfire so not as much air is pulled in so vacuum drops during that moment.
Even a weak fuel injector can cause less power to crank so slows it a bit.
Or a cylinder does have worn rings or exhaust valve seat.
That cylinder is getting air from other sources besides the intake manifold so vacuum level drops on that cylinders intake stroke.

The intake stroke for each cylinder is what creates the vacuum in the intake.

The IAC(idle air control) valve can also cause up and down movement.
If you hold RPMs steady at say 2,000 that would take IAC out of the picture, vacuum should stay steady.

Your vacuum level seems OK, so no reason found there for the lack of power.
If it was down below 15" and steady it would indicate engine issue

Doesn't mean its perfect, lol, but exhaust looks clear and 17" is not bad for a 100k miles, could have a small vacuum leak, I would expect 3.0l to be 19"

Thanks for the help guys...I guess she can just drive it until the problem gets worse or shows itself with a check engine light. If it keeps running fine and doesn't cut out or nothing, she might drive it for years that way. Thanks again.