Slow Acceleration, Tops Out at 45-50, No CEL

I have a 2003 Protege DX with 2.0 engine, auto transmission.

A little background info on the car. Engine has close to to 200,000 miles on it, burns oil like crazy, but still good gas milage. Uses 1.5 quarts between every fill up.

A few days ago during lunch, I went and put more gas in it and topped off the oil and went back to work, 1.5 mile trip. When I drove it home that evening, about 15 miles into the 25 mile trip, it stated having problems keeping its speed at 65mph, so I got off and took the frontage road home, where there is less cars and a slightly slower speed limit. From there, its been experiencing very slow acceleration and won't go any faster that 45-50 mph, even with putting the pedal to the floor. It seems like there is no more power to give, plus it seems like it wont change gears until it's very high in rpms. Check engine light has not come on at all during this. Also, the fan comes on pretty quickly even though the engine isn't over heating. The engine doesn't sound normal, sounds almost like its half working. I've already changed out the plugs and coils and checked the air intake for cracks and cleaned the MAF sensor and the problem still persists.

You replaced both coils, wires and plugs? The MAF and primary O2 could cause this but the ECU is pretty good at throwing a code for them when they fail. Should be an easy fix once you have some time to look around under the hood but I would start with ignition and fuel delivery. The fuel filter is in the tank in these cars but a failing pump or clogged filter/injector or bad ignition system is where I would start.

Burning oil can lead to a lot of secondary issues and may be causing your issues. Not only does oil clog spark plugs and fowl O2 sensors and catalytic converters, you will also have a bunch of fuel entering your crankcase. Not only would it act like seafoam, loosening sludge and carbon, which can then increase the viscosity of the oil and potentially plug small oil passages, it also does not lubricate like oil does so your bearings are going to see a lot more wear and friction. I think you should start with fixing the oil leak and then do a tune-up (replace air filter, plugs ,plug wires, fuel filter etc.)

Also, its possible that the cylinders in which the oil is leaking into isn't working as efficiently as the rest, ie the oil is causing a partial misfire or inefficient air/fuel burn. The transmission thing maybe related but it may also be due to the fact you have an old transmission with low hydraulic pressure.

Thanks for the suggestions! Turns out the problem was a clogged catalytic converter. I ended up taking it out, soaking it for 24hours in dish soap and water, then scrubbed it good and rinsed for a while. Not a 100% effective im sure, but it did the trick and the car runs good again.

Just take a big metal rod and smash the element to pieces and hollow the pipe out, that way you won't have to worry about it again and power will be restored.

hornsfan10609 said:

Just take a big metal rod and smash the element to pieces and hollow the pipe out, that way you won't have to worry about it again and power will be restored.

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Rofl... yeah just dont tell the inspector you did this (whistle)

Neither of my MSPs have cats and have been inspected for years now. As long as you don't live in Cali you should be fine, why would you tell them anyway?