No Power!!

[Wrangler98]

I hope someone else has had this problem so you can help me. I live in upstate NY so we have alot of snow and cold weather. I got a 1998 Jeep Wrangler Standard trans. About a week ago I started it up and drove around not thinking much was wrong, so I tried to power brake just because I hadnt in a while and the jeep stalled when I tried it, I couldnt get my rpms up high enough and it just couldnt get enough power to do it, and now It maxes out the rpms at about 2500 and I have to shift and when I get to 3rd it starts to jerk and feel like its goin to die. Then i have to get to 55 in 4th gear and then shift to 5th and it loses speed in 5th, itll go down to about 50 mph and i have to downshift to get back up to speed. I hope someone can help me!!

 

[SteelHeadz]

Does it progressively get worse as the engine gets hotter?

 

[Wrangler98]

no it actually seems like it gets better

 

[Bounty__Hunter]

Did the 'check engine' light come on?

 

[Wrangler98]

no, no lights are on, thats what I dont get. Maybe its the spark plugs?

 

[SteelHeadz]

The symptoms you've described relates to a plugged Catalytic converter. However, the temperature being hot and engine performance gets better doesn't fit the Characteristics. I wonder if the Ambient temperature has anything to do with that. if it was the spark plugs, wouldn't it have misfires?.a possibility could be a worn Camshaft lobes. I'll do some research on this . if you could, gather up some more symptoms. Bounty_Hunter should also be able to give you some guidance on this.

 

[Wrangler98]

Alright, its not the cat converter, I did a couple tests on it that my local jeep buddies told me to try, also im getting roughly 11-12 mpg now, if that helps at all.

 

[TJ_Jeep]

Wait are you running 31's on a 4 cyl with stock gears?

 

[Wrangler98]

nahh, I mines a 6 cyl.

 

[mud4feet]

Possibly your O2 sensors, although it should have thrown the CEL (Check engine light) if it's that bad. Happened to me with my four banger a while back. Noticed my gas mileage getting REALLY bad and was gradually losing power. Alot like your symptoms. Changed out my O2 sensors and everything went back to normal. Just a thought.

 

[TJ_Jeep]

nahh, I mines a 6 cyl.

Oh ok because if it was the 4 then there was half your problem but the 6 should do fine in 5th with 31's i have 35's and 5th is just a joke

 

[SteelHeadz]

Check for a worn camshaft. WORN CAMSHAFT LOBES-- helpful tips. Not all of these symptoms may be present. If you have two or more of these conditions you should at least consider a worn camshaft. 1.) Engine backfires under acceleration 2.) Long Term Adaptive Memory is highly negative (-10% to -33%). Higher LOAD adaptive cells are usually more negative than idle or low load cells. 3.) The engine acts as if it hits a rev. limiter. 4.} The automatic transmission equipped vehicles may not shift at wide open throttle. 5.) Abnormal engine cranking compression. If the camshaft lobes are worn the compression maybe higher than normal (this is the result of reduced valve overlap at cranking speed), If the base circle of the camshaft is damaged the valve may lift slightly off of its seat when It should be closed. This would result in lower compression than normal. Make sure you what is normal for this vehicle is measured on your compression gauge. 6.) The engine has a fluctuation in engine idle vacuum. 7.) Spark knock REMEMBER: If you only have one symptom it is unlikely that the problem is caused by a worn camshaft.

 

[Wrangler98]

hmmm im pretty sure i only have one of those symptoms but im not sure once my taxes come back ill probably put the jeep in the shop

 

[mud4feet]

Wouldn't hurt to pull your spark plugs and take a look at them, either. Good yield some clues.