Pat, did you ever have the lower intake checked as Gstacey suggested? He is the Caddy guy, and pretty knowledgeable. Aslo fuel pressure been tested yet? Results? I will look for TSB's(technical service bullitens). No TSB's But this is what to check:
This test determines if MAF sensor is providing proper readings to the PCM. MAF sensor is a high frequency device that measures the rate of airflow through the throttle body. MAF sensor outputs a series of pulses that varies in frequency with airflow. PCM uses this signal for fuel control.
MAF sensor readings during acceleration will be much higher than those during deceleration or idle. PCM calculates what MAF sensor reading should be from the sensor under certain conditions using engine speed (RPM), throttle position, and altitude parameters. When these test conditions are met, PCM will compare its calculated MAF value to the actual value received from the sensor. The calculated MAF reading is calculated by comparing MAP, RPM and IAT values. If difference between calculated MAF and actual MAF is too great, DTC will set.
1. Perform POWERTRAIN ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK, then go to next step. 2. Using scan tool, check for stored DTC(s). If DTC P0106, P0108, P0112, P0113, P0300, P0401, P0441, P1108, P1404, P1406, P1441, P1508, P1509 or P1645 is also present, diagnose affected DTC(s) first. If DTCs are not present or after diagnosing affected DTC(s), go to next step. 3. Check vacuum leaks at MAF sensor seal, throttle body spacer, intake manifold, PCV, EGR valve, plate or tubes and brake booster and hoses. Repair as necessary and retest. If air leak is not found, go to next step. 4. Check for stuck or incorrect PCV valve. Check for air (unmetered) leaks at oil dipstick tube or oil filler cap. Repair as necessary and retest. If vacuum leak is not found, go to next step. 5. Using FREEZE FRAME and FAILURE RECORDS data function on scan tool, duplicate conditions under which DTC P0101 was set. If DTC resets, go to next step. If DTC does not reset, see DIAGNOSTIC AIDS. 6. Go to DTC P0106 and perform diagnostic test, then return to this step. If repairs were necessary, verify repairs and retest. If repairs were not necessary, go to next step. 7. Replace MAF sensor and retest.
For intermittent setting of DTC P0101, use FREEZE FRAME data under which the DTC set, looking for faulty data from other sensors which may set this DTC. An improperly installed air cleaner or a distorted snorkel may cause DTC to set. Check for improper air cleaner or snorkel installation.
Tuesday, November 2nd, 2010 AT 11:34 PM