97 Wrangler loss of power

I have a 97 Wrangler, 4cyl with auto trans, no A/C, 130,000 miles on the clock.

About a week ago the Jeep started to suffer from a lack of power: it will run and idle fine, but when moving up to freeway speeds (>50mph) it feels like it is struggling. There is no obvious misfire or hesitation in the engine - it just feels weaker than normal . Actually it's a little like when the A/C is turned on a vehicle with a small capacity engine.

Any ideas where to start looking? I noticed that the radiator fan is always running (even at cold idle). I'm not sure if that should be the case or if this is somehow related to the lack of power.

Thanks in advance for any help Keith

Reply to
Keith Orbell
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Did you or do you have a noisy exhaust? Sometimes a problem with the catalytic converter will result in loss of power. If the substrate in the converter breaks up, it will sometimes be noisy before it starts to "plug up" the exhaust.

Spdloader

Reply to
Spdloader

Keith Orbell did pass the time by typing:

Sounds like a backpressure problem, plugged cat.

If you have a vac gauge, hook it to the intake and watch what happens when you bring up the RPMs.

Bring the engine to 2500 rpm and check the manifold vacuum for at least 15 seconds. If system vacuum is high and steady then the exhaust system is probably ok. If the vacuum drops it's probably a clogged cat.

Now if you replace the cat the question is what clogged it. Usually that answer is the O2 sensor. The O2 sensor usually fails slowly and as it does makes the mix richer.

An aftermarket high-flow cat should set you back about $100 with install at a good local shop.

Reply to
DougW

I like to look at the cheap stuff first. Inspect the distributor cap, rotor, plugs, etc. Did you leave the emergency brake on? Spark plug wires can fool you too. How many miles on them?

Earle

Reply to
Earle Horton

I like to look at the cheap stuff first. Inspect the distributor cap, rotor, plugs, etc. Did you leave the emergency brake on? Spark plug wires can fool you too. How many miles on them?

Earle

Reply to
Earle Horton

I like to look at the cheap stuff first. Inspect the distributor cap, rotor, plugs, etc. Did you leave the emergency brake on? Spark plug wires can fool you too. How many miles on them?

Earle

Reply to
Earle Horton

The other suggestions like a possibly bad/plugged catalytic converter are good but also be aware your upstream (nearest to the exhaust manifold) 02 sensor can cause a dramatic loss of power and fuel economy when it goes bad... and they do go bad. See if you have any stored diagnostic codes using the procedure at

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which might tell you what the problem is. When doing the three on-off-on ignition sequence, make sure to give it time to start displaying the codes, it can take as long as 5-10 seconds before the codes begin appearing so have patience. If you did the ignition key sequence properly, you will at least get the usual '55' code which is always shown and follows any other possible codes. Jerry

Reply to
Jerry Bransford

P.S. Though that website says to count the number of flashes on the Check Engine light, there's no need to count them on your '97 TJ. The actual numeric codes will appear in the odometer display.

Jerry

Jerry Bransford wrote:

Reply to
Jerry Bransford

Fuel filter?

-- Old Crow '82 FLTC-P "Miss Pearl" '74 XLH chopper(somebody else's baby now) BS#133, SENS, TOMKAT, MAMBM, DOF#51, DH#2 "There's only 1 RE"

Reply to
Old Crow

The fuel filter is part of the fuel pump. I just had to replace my pump. It came with the inner and outer filter.

Try to burn up most of your gas first. My pump died with most of tank full. What a b*tc*!

Reply to
Scott in Baltimore

I work at a Chevy dealer as a tech. Seems the first thing most people do when they believe the fuel pump is going bad is to fill the tank. I

*hate* dropping tanks with 20+ gal of fuel in 'em.

-- Old Crow '82 FLTC-P "Miss Pearl" '74 XLH chopper(somebody else's baby now) BS#133, SENS, TOMKAT, MAMBM, DOF#51, DH#2 "There's only 1 RE"

Reply to
Old Crow

Thanks to everybody for the advice.

The catalytic converter could well be the problem here - the exhaust is currently pretty noisy and has been for a while. Furthermore, I replaced the upstream O2 sensor last year after it went bad - perhaps this has had a delayed impact on the cat.

Thanks again, Keith

Reply to
Keith Orbell

Sometimes the catalytic converter can start going bad and take out the O2 sensor. It is recommended to replace the O2 when replacing a cat. Your converter may have been going bad last year when you replaced the sensor, and it took until now for it to cause the loss of power symptom.

Again, just speculation, nothing is as good as being there to check in person.

Good luck,

Spdloader

Reply to
Spdloader

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