Having a hard time accelerating over 45mph

[Db0790]

Hello,
A couple of days ago I was driving my 03 Ranger XL 2.3l and about to get onto 95. I floored it a little and then lost power and then the truck shuttered a little. No CEL came on. Tried to accelerate again and couldn't go past 45 mph. So I pulled over and let it sit for a little while.

I started her up and still no CEL, and after forcing it can get up to 55mph. And it feels like it loosened up a little. I noticed the rpms won't go any higher than 2500 as well. I can't tell if it's vibrating or if it shuttering. But, its doing one or the other.

Not sure if it's related, but the oil pressure gauge was a little low too at the time. Just throwing that out there.

Anyone have any ideas or experienced this? I googled a few symptoms and got stuff from clogged cat converter to bad neutral safety switch to bad plugs and wires.

Any help would be greatly appreciated! Thanks in advance

 

[RonD]

Sudden loss of power could be Cat or muffler collapse, same for limited RPMs.

Not a bad place to start, Vacuum gauge would be best to trouble shoot that.

Good read here for that and other tests: http://www.gregsengine.com/using-a-vacuum-gauge.html

Vacuum gauges are cheap and one of those tools that will never use it's usefulness with gasoline engines.
No matter how many things they strip off the outside, i.e. distributor/carb, or how many controls or sensors they add, gasoline engine is still an air pump, so vacuum gauge can tell you ALOT.

 

[Db0790]

Thanks RonD. I'll take a look at that and see what I can find out

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[tomw]

Those are good places to look, but I'd also add the fuel pump and filter. If the filter 'finally' got enough gunk, it could limit flow. Or the sock in the tank on the pump inlet tube could be clogged with stuff, limiting flow, and thus limiting how fast you can run the engine.
Quick check of pressure and delivered fuel volume would tell.
I do not think a catalytic converter failure would happen so catastrophically as to go from running down the highway to crawling in a few seconds. There's be some other symptoms before it clogged that much.
If you have an air filter that is full of stuff, it will limit air, the computer will respond by limiting fuel the same as if you had a bad pump or filter. Can't hurt to check that.
tom

 

[Db0790]

Thanks for the info. Probably way overdue for a fuel filter change anyway. I bought the truck back in January for $1100. It was severely neglected. It's been a roller coaster ride so far. Fix one thing, then something else goes kinda thing. Just finished replacing the whole front suspension and tie rods, just to make it safe to drive. So it would figure that something else not suspension related would go. Had to replace the MAF sensor a month ago.

So thanks guys for input. Definitely could use as much guidance as I can get. Much appreciated!

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[Tedybear]

Had a '79 T-Bird long while ago.

It would go from doing 60mph...and suddenly without warning of any type drop to "Can't do more then 30mph". It would clear itself up after a few moments...and do it again at random times.

In this one case it was a plugged converter.

Good advice is always to verify before being a parts changer. Vacuum gauge will be a huge help! And a fuel pressure gauge will also help!

If it's doing this at all times now, another good test-but not much a DYI'r can do easily would be an exhaust back pressure test. But the vacuum gauge should give direction as well.

S-

 

[ratdude747]

If it's doing this at all times now, another good test-but not much a DYI'r can do easily would be an exhaust back pressure test.

Remove an O2 sensor? If there's a backpressure problem, pulling said sensor should "correct" the issue (not that such is an actual fix, mind you).

 

[Db0790]

I will have to try the back pressure test and vacuum test on Friday. Have a busy family life this week.

I did drive it around today and it seemed a little better, but not 100%. I did read that cat converter failure is usually due to something else going bad.

I did forget to mention that I had a small oil leak coming from the seal that on top of the engine. I added some Barr's leak engine leak to hold me over till I could replace the gasket. Do you think this could have affected the cat any? The issue did happen about a day and a half after I added it. Coincidence?

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[Db0790]

The RPMs are still refusing to go over 2500

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[tomw]

I do not think driving around is going to fix the problem.

What was the fuel pressure at idle? At idle with the vacuum line removed from the fuel pressure regulator? How much fuel did the pump deliver in 15 seconds?
Have you checked that the battery cables are tight? They can be loose and cause intermittent problems with the ignition and the pump and the computer. The light may or may not come on, and the engine may just run slower and slower and slower, losing power over a short time.
What is battery voltage at rest? What is battery voltage with the engine at idle? At idle with the headlights and blower motor on HI?
Measure on the terminals rather than the posts to insure you are measuring system voltage(actual voltage on the wires) rather than inside the battery(posts).
tom

 

[Jimmyrig]

Catylitic converter is my guess. If the truck has a lot of miles on it and especially if it was run loaded a lot or lugged around. I've had them plug with carbon from the engine and do exactly what you described. My personal fix is a piece of exhaust pipe where I delete the cat, but there's no deq where I live

 

[Db0790]

Hey guys. Thanks for all your input so far. I decided I need to take the truck in to get it looked at. Haven't done it yet but will soon. My tiny little brain is having a hard time with figuring out how to do the tests.

But in the meantime, I just changed my fuel filter and about to change my spark plugs and wires. I pulled out the coil to the plug that's the farthest away and there was oil on it. It seemed like a lot of oil. So I stopped working on it to see what to do next.

Also there are 3 small hoses that are connected by a plastic T connector. Well the plastic connector is broken and brittle and the hoses are just hanging there. Do you think the oil on top of the plugs as well as the hoses could be a factor into the issue?

Thanks again for all your help!

 

[Mark_88]

Oil on the plugs usually indicates bad rings or valves...but you would be having issues all along if that were the case. My "guess" is to do with the cat also ...if it plugs the pressure cannot leave the engine in the same manner...it backs up in the engine and forces the oil up past the rings...further complicating the firing...

I had a bog down problem similar to this...the engine sounded like it was being choked...it was the cat...I later found that the insides of the cat were pretty much completely blown out...probably about the same time my bogging problem seemed to disappear...

But if you are overwhelmed and have money to burn it's best to let a shop do the diagnostics...all the suggestions seem like easy enough tests to do...but it can be mind boggling for sure...

 

[Db0790]

Thanks man. Yeah I have a patience problem as well. Definitely overwhelmed. Don't really have money to burn, but would prefer things got done Right. I can do most repairs when I know for sure what's wrong with it. Just figuring out what it is is the problem

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[Db0790]

Jimmyrig, did you delete both cats or just the 2nd one?

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