Any reason for a car to get weaker over time?

[fuzzybabybunny]

2000 Toyota Echo Coupe 125K miles

My car's been getting on in age and miles and I feel that it's definitely less peppy than before. Acceleration doesn't feel as good, climbing up hills is tougher - inclines that I'm pretty sure would have been fine in 3rd back in the day now need to be gunned up in 2nd.

My air filter is pretty clean.

I've always done oil changes on time.

New spark plugs.

Tires inflated properly.

Still getting 38mpg.

Don't believe there is any blockage in the exhaust - if anything there's probably a small hole judging from the sound.

My clutch is mildly worn. When doing the 0-60 I don't get that jump anymore going from 1st to 2nd. Doesn't help that I taught someone how to drive stick a week ago and we got some clutch smoke.

Any ideas?

 

[woodie1]

Would be helpful if you provided us with the make/model/year/miles on the vehicle in question.

 

[MotF Bane]

Mechanical devices age.

 

[randomlinh]

125k miles... on a commuter car.... it's going to age no matter what.

 

[PhoKingGuy]

Well seeing as how you treat it like a piece of farm equipment im not surprised.

 

[brblx]

100hp engine after ten years is probably more like a 90hp engine.

125k isn't a huge amount of mileage, but yes, engines do get a little weaker. does it feel it's running strong and even when you accelerate hard? got enough go that you can downshift and change lanes or pass without getting run over? no abnormal noises and no CEL? if so, it's probably fine. it's a toyota echo, if it's doing it's job just leave it alone (but keep up your regular maintenance).

 

[Howard]

Spark plug wires? Spark plugs with proper gaps?

 

[exdeath]

If your clutch is slipping you'd know it. Did you switch to cheaper gas or anything? Is the weather hotter or more humid in your area recently?

If it's a mechanical issue (eg: clogged filters, etc) you would normally have non normal symptoms like hesitation or stalling. It could still be something like a worn accessory pulley bearing or AC clutch or brakes or something dragging, but unlikely without other specific symptoms like increased noise. It seems like everything is working fine, it's just not where it used to be.

To really get to the bottom of it you'd have to have a professional tuner look at key parameters like sensor inputs and ignition timing and fuel trim. Sensors like temperature sensors and O2 sensors can wear or age and drift and diminish over time and affect peak engine performance but still be within acceptable range. O2 sensors are notorious for getting "weak" with mileage and skewing fuel trim. Theoretically sensors are solid state devices that should never fail, but they operate under extreme conditions in a car engine (exposure to high temps, carbon/soot buildup, corrosion, etc). Same goes for aged or dirty emissions controls which can impact engine performance but still be considered to be functioning normally and not causing any adverse symptoms.

Something trivial like ignition timing being retarded 2 degrees because of a "worn" sensor that is reading a a few tenths of a volt higher or lower than normal would cause a noticeable loss of power, especially on a smaller engine that isn't all that powerful to begin with.

You'd need someone experienced specifically with ECU tuning and datalogging and EFI optimization. A general mechanic doesn't really care about this stuff, but it's the best way to understand what's going on.

Data logging is your friend.

Or it could be that you are just used to it, and have recently driven a more powerful car and it's just in your head? 😛

 

[brblx]

as silly as it sounds, the most direct test would just be to dyno it. if, when taking into acount flywheel versus wheel horsepower ratings, you're more than maybe 5-10% down from the factory rating, maybe there's a little problem somewhere (or a small collection of problems contributing collectively).

that's likely just a waste of cash, though. if the car behaves normally, it's probably running fine. something that would make the car run poorly and make less power, like an air or fuel restriction, or a misfiring ignition system, would cause symptoms and probably turn on the check engine light (for fuel trim if nothing else). i've found very sensors that reported normal in-range values despite being bad. MAF's are about the only thing that often won't set a code for themselves, but they'll trip the light for fuel trim eventually. PM gen and hall effect sensors really don't wear to any noticeable to degree in normal operation. o2's work fine as long as they're not gunked up, in which case the signal would be abnormally low.

if he's getting the same MPG, most of this is a moot point, anyway. minor tuning problems would certainly affect mileage as much as power.

 

[ChaosDivine]

A transmission flush with quality fluid would really help (check the ATF type).
Also change out the fuel (not oil) filter and swap in fresh brake fluid (make sure whether it's DOT3, 4, 5 or 5.1 - although DOT3 and 4 are supposed to be compatible, they use different chemistries).
Power steering fluid wouldn't hurt either (again check the ATF type).

Last thing I can think of is dumping a little SeaFoam in the tank.

 

[Kadarin]

Run compression and leakdown tests on it. Likely what's happening is that as the engine gets older and has more miles on it, the piston rings and/or valve seals wear, causing the cylinder to not hold compression as the piston approaches top dead center.

 

[PandaBear]

1) reduced engine compression
2) increase drive train friction (bearings - wheel, alternator, AC, etc)
3) ignition components worn out (coil, plugs, wires, etc)
4) plugged injectors, valve deposits, lazy O2 sensor, dirty intake manifold, clogged EGR valve, clogged PCV valve, and commonly omitted issue of exhaust leak result in less draft effect in exhaust/intake valve overlap -> less power.
5) new tires have more rolling resistance than the OEM junk/dangerous no-traction tires.
6) alignment off (mostly toe)
7) sticky brake pads/shoes