97 TJ acceleration problems and engine noises

Hi everyone,

I just bought a 97 2.5L 5 speed just to give you an idea of what I have. First thing, when I get to 4th gear it takes a very long time to accelerate to 55-60 mph. I will put it in 5th only when on a long highway, but it never goes up in speed at all. I noticed that when I first bought it back in March. I didn’t think anything of it except that it needed a tune up since it was nearly 25 years old. But now more problems are starting to arise. When in gear and I let off the gas there is a clicking kind of noise similar to what sounds like a lawn mower backfiring and the floor of the Jeep gets pretty warm too after driving for a while. this all happened in the last 3 or 4 times I’ve driven it. Plus, as of last night there is a strong smell coming in the cab of the vehicle. I’m thinking I might have a pretty bad exhaust leak, but am not sure if anything else could be the matter with it either is why I’m coming to y’all.

23 year old 4 cylinder Jeep with xxx miles… you don’t say…

The engine was weak when it was new. It is weaker now.

The warm floor really makes me think the catalytic converter is plugged or the heat shield for the cat fell off a decade ago. If the cat is plugged it can cause leaks. Pressure checking the cat is possible with a pressure gauge tapped into the O2 sensor bung. Anything more than 1 or 2 psi at full throttle is clogged.


Ah sorry about that. Only has 116k miles on it currently. I’ll check the pressure of the cat in the morning.

Agree with @Mustangman,

The engine is underpowered and a rather primitive design. My son has one and we had to replace the engine @ 100K miles. My wife’s friend who worked at a Jeep dealer said the 4 banger had thin cylinder walls and anything over 100k was a bonus. They replaced a lot of them at that age.

Replace the coil, spark plugs, rotor and distributor cap. If you have a misfire, the cat will get hot. A simple fix may clear this up. But if this has been going on for a while the cat may well be toast

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