Help! Losing Power

[Daveos]

This is only happening after starting the jeep when it is hot. A cold start wont produce it. It only lasts for about 30 - 40 seconds before going back to running normal. It is not throwing an engine light.

Hot start
Runs good for about 20 - 30 seconds
Runs like crap for 30 - 40 seconds
Runs good.

Cleaned evap canister, changed purge solenoid, spark plugs a few months ago, cleaned throttle body, new TPS, new battery, seafoam. Any help / direction would be much appreciated. I am a broke college student.

I have posted elsewhere for help, figured this may be a better place for the KJ.

JEEP:
2003 KJ Liberty Sport
102K miles
45RFE Trans
3.7 V6

 

[keeponjeepin]

If you can, run a compression check when the engine's hot. You could have a valve seat and/or a lifter problem - wouldn't send any codes.

 

[Daveos]

If you can, run a compression check when the engine's hot. You could have a valve seat and/or a lifter problem - wouldn't send any codes.

It doesn't run bad if I start running it when it is cold and it heats up. It is fine even after it gets hot. It is only after it heats up, I shut it off and wait a few minutes, then start it up and leave. It will run good for about a minute, then run like crap for about 20 or 30 seconds, then it will run fine again. Wouldn't a bad lifter / seat cause more consistent problems?

 

[keeponjeepin]

Yes and it would get worse. This is a long shot but check your radiator level. Make sure you look inside the fill tank and fill it up. It could a little low on anti-freeze and when the engine sits the water temp is rising - thus making it run bad until the water starts flowing again, cooling the engine. Check the fill tank cap also, they tend to go out around the miles you have.

 

[Daveos]

Yes and it would get worse. This is a long shot but check your radiator level. Make sure you look inside the fill tank and fill it up. It could a little low on anti-freeze and when the engine sits the water temp is rising - thus making it run bad until the water starts flowing again, cooling the engine. Check the fill tank cap also, they tend to go out around the miles you have.

Well, it's not consistent at all. It is only on a warm start. Coolant level is good. I drove it for 20 minutes today from cold start with no issues at all.

I'm starting to think it may be an evap problem. My evap canister was clogged and was only causing problems when I got gas a while back.

Confused.

 

[keeponjeepin]

Very odd... I'm trying to think of tests that don't cost you money. Let me think some more.

 

[Porkchop]

Humm Kinda sounds like a air temp sensor starting to fail. Can you read the ODA when this happens like from a scan gage. Maybe check wires or the plug.
With out having it here this is only a guess but something you might want to check.

 

[Daveos]

Humm Kinda sounds like a air temp sensor starting to fail. Can you read the ODA when this happens like from a scan gage. Maybe check wires or the plug.
With out having it here this is only a guess but something you might want to check.

Thanks for the help guys.

I wasn't aware it had an air temperature sensor? Found its location in the manual. Be inspecting it tomorrow.

 

[seabass1858]

I would also check the air temp sensor, had the similar problem happen to my 89 chevy beretta air temp sensor changed runs like normal.

 

[Porkchop]

Iat on a 03 I think its on the left front intake. On my droid cant look it up and paste sorry.
Oda is in the griil

 

[Daveos]

Iat on a 03 I think its on the left front intake. On my droid cant look it up and paste sorry.
Oda is in the griil

Thanks

I found it in the manual. See if checker has one tomorrow.

 

[Daveos]

Looks like the air temp sensor may have been the problem. See how long it goes without loosing power. The one I took out was coated in crap.

 

[Porkchop]

Hope it works out for you.let us know. Sounds like you didnt waste your $ replacing it any way.

 

[Daveos]

Hope it works out for you.let us know. Sounds like you didnt waste your $ replacing it any way.

Thanks. Yeah, this week has been a money pit. ****** fluid change, oil change, new battery, new TPS, new ATS, new Plugs, Throttle body clean. Hopefully that takes care of it.

 

[J'sJeep]

Check and see if the AC Compressor is bad.. I know it is funny but it could be going bad (like mine and another fellows on a thread we've been posting on regarding stalling) and it could be causing a bit of drag on the engine when the magnetic clutch engages and the compressor is being cycled with the serpentine belt. hopefully that is not it, it is easy enough to disconnect though and then you can check and see if it duplicates... currently i have mine disconnected and have not had the stalling replicate yet (15-20 miles so far). worth a shot and free fix! just make sure you zip-tie it up and out of the way before operation

 

[Daveos]

Check and see if the AC Compressor is bad.. I know it is funny but it could be going bad (like mine and another fellows on a thread we've been posting on regarding stalling) and it could be causing a bit of drag on the engine when the magnetic clutch engages and the compressor is being cycled with the serpentine belt. hopefully that is not it, it is easy enough to disconnect though and then you can check and see if it duplicates... currently i have mine disconnected and have not had the stalling replicate yet (15-20 miles so far). worth a shot and free fix! just make sure you zip-tie it up and out of the way before operation

Thanks ,

I'm thinking it was the air temp sensor. It hasn't done it since I replaced the sensor yesterday morning. We'll see tho.

 

[Daveos]

Now the idle when it is warm has gotten more choppy. Time to replace the Crank shaft position sensor?

 

[rockymountain]

Did you remove and clean the IAC?

 

[Daveos]

Did you remove and clean the IAC?

Yup, IAC, throttle body, and new TPS. The IAC was pretty bad, but it cleaned up okay. Should it have been able to move easily? It was rather stiff.

Also replaced the battery, new air temp sensor, new air filter, newer fuel filter.

 

[rockymountain]

What kind of plugs?