Losing power at high speeds

[thrasher141]

Hi,
I have a 1983 Camry, manual transmission. I have noticed the last few weeks that the car sometimes loses power when I'm trying to accelerate in fifth gear (often but not always when going up a slight hill). Happens a little bit in fourth sometimes too. When I step on the gas, it almost sounds like one of the cylinders isn't firing (though I don't think that's the case). If i let up on the gas a bit, it sounds normal again. But I can't get much power.

This behavior roughly coincides with my muffler rusting out and finally I took the muffler off a week or two ago. Could a lack of back pressure be causing this loss of power? Or should I suspect something like fuel pump (fuel pressure)? I do still have the catalytic converter...the exhaust system is intact up to the point where there should be a muffler.

Thanks!

[lionheart03]

I had a similar problem with my 91 Camry. Loss of power at high speed, fuel economy getting bad, etc. Ended up being a plugged cat. After being "fixed", a major increase in fuel economy and power!

[thrasher141]

Thanks for the reply. What is a "plugged cat"? Catalytic converter? And what is shown in that picture?

['88 All-Trac]

That is a picture of a half-gutted catalytic converter. I also had this issue, and fixed it by gutting or "rodding" the cat out.

[thrasher141]

So if you do that, I'm assuming the cat ceases to serve its purpose of cleaning up your exhaust, but at least your engine will run better?

['88 All-Trac]

When the cat warrants being rodded out, it is increasing emissions if anything; the ridiculous fuel usage at high speeds is a real drag.

It will no longer burn CO into CO2 but your mileage has the potential to increase drastically. Remember, though, that the car will be somewhat louder unless it i a Cal-spec emissions vehicle, which will have a second one mounted under the engine. If you would like to retain a catalytic converter, you can have a 2" - 2 1/4" unit welded in at most exhaust shops for a reasonable price, but a replacement stock unit can run several hundred dollars... Which is why I rodded mine out and then because the car doesn't need to be smogged I straight-piped it and slapped on a glasspack. I went from pulling 27mpg highway on a good day to 38mpg if I'm trying- 30-35 with regular cruising.

[Camry84]

I guess I'm on the O2 sensor bandwagon this week but I'd certainly check it out before spending too much on anything else, assuming that you have tuned your car up (plugs, distributor cap, rotor, wires) first.

Cat could be bad too but a new Denso O2 sensor is not too expensive, I just got one for about $42 shipped. Hoping it will solve a very similar problem on my 84 Camry. If you do get an O2 sensor, be sure to go OEM ... (i.e. Denso).

Best of luck!