2006 Grand Cherokee idling and downshifting problems

[LeeB]

2006 Grand Cherokee with 4.7 V8, 104,000 miles has been having some weird idling issues for a few months. When idling it revs and backs down revs and backs down over and over again.

About a week ago I towed about 1,500 pound trailer 600 miles. Then a day or two later several indicator lights came on, and it seems to be idling even more rough. And now whenever it downshifts, "something" makes a loud “clunk.”


Lights on are: Check engine, ESP, BAS, and traction control.
Pulled OBD code: 0068


According to P0068 MAP/MAF - Throttle Position Correlation DTC

P 0068 could be mass airflow sensor, throttle position sensor or the Manifold pressure (MAP) sensor.
I'm in a bit of a bad spot as I'm going through a divorce and am flat ass broke, so I need to figure this out on my own. AND I'm not much of a mechanic!
Ideas on the first place to start?
Looking under the hood, I'm not even sure where any of those parts are!
Is this possibly the location of the MAP?


http://i.imgur.com/PNbGm5o.jpg



I'm lost. Thank you in advance.

 

[JPNinPA]

Check connections of the TPS and IAC. Move the throttle butterfly valve back and forth several times. 25+!

Also clean the TB and IAC.

If you change sensors use OEM sensors only.

 

[LeeB]

Sorry, I'm a complete boob when it comes to this. What is the IAC? And the TB and IAC?

Thanks for your response.

 

[JPNinPA]

Sorry, I'm a complete boob when it comes to this. What is the IAC? And the TB and IAC? Thanks for your response.

No worries.

TB is the Throttle Body on a fuel injected engine this controls the air intake while driving.

IAC is the idle air control valve on the side of the TB that controls the air intake during idling. Both of these collect soot like dirt that causes idling and running.


The TPS. (throttle position sensor) is a spring resistor on the valve in the TB that reports the position/air intake to the PCM (power control module/engine control module) and adjusts the injector output.


http://www.jeepforum.com/forum/f9/cleaning-iac-throttle-body-write-up-dummies-1114849/Clean TB and IAC

 

[LeeB]

Thank you so much! Like I said, I'm pretty hopeless under the hood. Years ago, when cars had giant cavities with an engine in them, I did okay. But now, it's sensors and wires and computers, and I'm a complete loss. Your information and advice is at least a starting place.

Thank you again!