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Occasional loss of power

Chasitek

TJ Enthusiast
Supporting Member
Joined
Feb 19, 2018
Messages
627
Location
Chapel Hill, NC, USA
So I have been experiencing an occasional loss of power. I guess I would call it more of a loss in acceleration. When my jeep is completely warmed up and i've been driving for a bit, it sometimes takes FOREVER to accelerate and yes I know jeeps aren't supposed to accelerate quickly but it's just inconsistent acceleration. Sometimes it accelerates fine and sometimes not. (has nothing to do with uphill downhill, assume i'm always talking about a level surface) Also, sometimes on the highway, it won't go past 60mph on level ground and sometimes it'll go 75. It's a 97 2.5L with a 4.0 throttle body and 2.5L throttle body spacer with no bore. (yes i know it doesn't increase power) I just like the more sensitive throttle response. I just replaced the spark plug wires, spark plugs were replaced just a few months ago, cleaned the distributor contact points. Engine has 250k miles but I just did a compression test and 3 cylinders had 175psi and one had 190psi so no problems there. I have a small exhaust leak at the manifold collector. Any ideas on what the problem could be? Also if I push the accelerator pedal to the floor, it actually loses acceleration but if I hold the pedal slightly above the floor it holds its power. What's that about? Thanks in advance for any help.
 

Steel City 06

TJ Expert
Supporting Member
Joined
Mar 12, 2019
Messages
4,264
Location
Pittsburgh, PA
If increasing the throttle decreases power, my first guess would be incorrect fuel/air mixture, or wacky timing. Perhaps the exhaust leak is messing with the computer and oxygen sensors?

Also, what RPM range is it bogging down in?
 
Last edited:

Briscoe44

New Member
Supporting Member
Joined
Mar 31, 2019
Messages
20
Location
Coquitlam Canada
Nope, No codes of any kind. I really just notice it after driving around a bit when it's warmer out and since it's been nice out lately, i've noticed it a lot more. I do have a mechanical oil gauge and sometimes when fully warmed up, idle psi is 40 and sometimes it's 60. It fluctuates a lot. I'll get some definite readings and report back but I do know it's inconsistent as well. Also, sometimes when i'm losing speed on the highway, I push the clutch in and re-engage 5th gear and it accelerates again. Maybe clutch related?


Hi guys. New member here. You might want to try replacing your throttle body sensor. Fairly inexpensive part. My 2004 would lose throttle when I tried to accelerate and this fixed my problem.
 
OP
Chasitek

Chasitek

TJ Enthusiast
Supporting Member
Joined
Feb 19, 2018
Messages
627
Location
Chapel Hill, NC, USA
Hi guys. New member here. You might want to try replacing your throttle body sensor. Fairly inexpensive part. My 2004 would lose throttle when I tried to accelerate and this fixed my problem.

Thanks. I’ll try that. Cross your fingers for me.


Sent from my iPhone using Tapatalk
 
OP
Chasitek

Chasitek

TJ Enthusiast
Supporting Member
Joined
Feb 19, 2018
Messages
627
Location
Chapel Hill, NC, USA
No engine codes stored or pending?
Nope, No codes of any kind. I really just notice it after driving around a bit when it's warmer out and since it's been nice out lately, i've noticed it a lot more. I do have a mechanical oil gauge and sometimes when fully warmed up, idle psi is 40 and sometimes it's 60. It fluctuates a lot. I'll get some definite readings and report back but I do know it's inconsistent as well. Also, sometimes when i'm losing speed on the highway, I push the clutch in and re-engage 5th gear and it accelerates again. Maybe clutch related?
 
OP
Chasitek

Chasitek

TJ Enthusiast
Supporting Member
Joined
Feb 19, 2018
Messages
627
Location
Chapel Hill, NC, USA
Did you ever figure out what the problem was
Seems to have been an exhaust leak. Haven’t really been driving it much as I just got another car and I had to replace the cat on my jeep since the weld around it broke. It seems to be a lot better ever since i replaced it. The cat was only a year old though. Wasn’t clogged or anything.
 

Cruz Hernandez

New Member
Joined
Oct 31, 2021
Messages
10
Location
Chandler Arizona
Hi guys. New member here. You might want to try replacing your throttle body sensor. Fairly inexpensive part. My 2004 would lose throttle when I tried to accelerate and this fixed my problem.

i’m having issues making it to 60 mph and i just replaced plugs coil and injectors could this be the problem?
 

Glockinacroc

New Member
Joined
Sep 4, 2022
Messages
1
Location
USA
Hi guys, new here, had the exact same problem, i would lose power on the freeway around 60 mph, then it would catch after accelerating a little more, ended up being the crankshaft position sensor, saw it on another forum and changed it. 30 dollar fix, haven't had the issue since.
 
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