New Jeep Owner...seeking help with RPM issues

[ashelby]

Good afternoon!

I recently bought a used 2008 Jeep Liberty 4WD and live in St. Thomas USVI. The islands are not very kind to vehicles and I am not a car person. I've been to both mechanic shops as well as a 'mobile' backyard mechanic to try and help me with some of these issues..my check engine light is always on and I have gotten codes for vacuum leaks but haven't found where they are.

Whenever I'm driving straight for a while (both uphill and flat roads) and pressing on the gas, I will feel a rumble and then watch as the rpm will drop from around 2000. This has happened since I bought the car.

A newer issue is that I can feel more resistance on my brake pedal as I push on it and if I'm idling my car will run at around 10-15mph and 1200 rpm without me putting my foot on the gas. If this is happening when I stop and put my car into park the rpm will shoot up.

Lastly, (not sure if this is at all related-- like I said I am not a car person), I live up a steep hill and my transmission oil temp light will come on infrequently. I've driven it for 30-45 minutes across island in the middle of the summer heat and this has never happened, only when I go up my hill.

My oil is changed, I've had my transmission serviced (twice), fan clutch replaced, and thermostat replaced.

Any help, advice, or ideas to why these things are happening is extremely appreciated!!

Thank you,
Adeline

Edit: the codes that the scanner picks up are P0457, P0456, and P0218

 

[John P.]

Hi and good afternoon, with a vacuum leak and your brake pedal becoming firm I would check the vacuum line going from the intake to the brake booster. It may have developed and crack, cut, or perforation and create the issue you describe. If you can post the codes you get from the obd scan that would help and prompt others to respond as well.

 

[ashelby]

Hi and good afternoon, with a vacuum leak and your brake pedal becoming firm I would check the vacuum line going from the intake to the brake booster. It may have developed and crack, cut, or perforation and create the issue you describe. If you can post the codes you get from the obd scan that would help and prompt others to respond as well.

Hi there John thank you so much! I'll look into that and also update my post with the codes

 

[John P.]

Awesome

 

[NavyStore]

Is your KK stored outside or in a garage? I live in the Seattle area, and haven't had these sort of issues, so I'd agree you have a vacuum leak - and heat/sun will damage the rubber hoses, even under a hood.

 

[Phil2020]

If you can no longer get vacuum hoses, everything's getting discontinued for Vacuum problems, if you zoom in you can see the fine cracks beginning to form all around the edge of the hose (see photo below)
You can use this type, (see photo below). Don't forget you MUST replace these hoses with "Oil Rated" hoses ONLY!

***REMEMBER *** When you change ALL hoses, rubber bushings, and rear and front rubber housings use AT-205 on them!
Buy a spray bottle from the dollar store and fill it up with the AT-205, then spray ALL the NEW/old rubber replacements, this stuff is fantastic and it'll help them last 3 times longer

Hope this helps ya