Alright Swedespeed, I am hoping you can come through and give me help once again!
2007 XC90 3.2 Awd with 122k miles
I Replaced the X-pipe (which contains down stream O2 sensors and secondary cats) because the flex pipes were rusted through and mid muffler last weekend. Took it for a test drive and everything was great. My wife drove to work and home on Monday with our little one on board...and the XC90 threw a whole bunch of new issues at me which do not appear to be related to my repairs last weekend.
I have been trying to diagnose this since Tuesday, the vehicle will accelerate normally with light throttle at low speeds, but as soon as the rpms get above 2500 the vehicle struggles to accelerate. If you jab the throttle to get it to kick down a gear and accelerate faster the transmission will drop a gear but the rpms struggle to climb. You can hear the intake sounds get deeper as it try's to get more air in the engine, but the rpms climb slowly and not smoothly. Feels like a stutter/misfire...I am not sure if one thing is causing and issue or multiple things.
Here are the codes pulled from Vida on Monday
The bottom codes for the manifold runner control (morning code) and misfire's (evening codes) are the new codes, the catalyst efficiency is from before I fixed the exhaust. Here is the timeline info
Here is the freeze frame from when the Intake manifold code was set
Here is the freeze frame for the misfire codes, since those 3 codes were set at the same time they all have the same images captured
I have since tested the operation of the Upper Intake manifold runner control through the activation's in Vida, I could hear and feel it open and close just fine. I could not get it removed to visually see it work. I also removed the coils from cylinder 1 & 3, coils are original and visually look Ok. I also checked the spark plugs for those cylinders and they still look new (replaced a year ago). I did swap cyl 1 & 2 coils to see if the codes would change. I disconnected the battery to reset things, I have gone on several test drives, 10-15 minutes at a time. No codes have popped up but the car still struggles to accelerate.
I took a graph screen shot in Vida of the MAF(mass air flow) and throttle postion. Gentle acceleration the 2 moved in unison on the graph. This picture is when I jab the throttle to kick it down a gear and try to accelerate, you can see the throttle opens and the MAF goes CRAZY! Is this normal to see for a MAF?
So I removed the MAF, clean it and reinstalled it. I received the same results. I unplugged the MAF and the car stalled. I restarted it and it had a very lumpy idle. I drove it and experienced the same struggling of acceleration.
So I ran another graph, this time showing MAF (blue), Throttle position (black), Fuel Pressure (red), Intake manifold pressure(green), and Fuel pump duty cycle(purple)
Here is a graph of very light normal acceleration, everything appears to be good...
This one shows deceleration and then a jab of the throttle again to accelerate. Throttle position goes up, Manifold pressure goes up, MAF is crazy again, fuel pressure didn't really change, the fuel pump duty cycle dropped during deceleration and came back up on acceleration.
Another shot, similar driving scenario, similar results
Anyone have any idea what's going? I have been scouring the internet all week for answers. Everything I have read any of these things could be the issue..bad MAF? Bad Coils? Bad intake manifold runner control? Bad Throttle Body? Vacuum leak? Bad thermostat causing the head to get hot and ruin the coils? Bad Fuel Pressure Sensor? Bad Pem? Bad Fuel pump? Crankshaft position sensor? Cam solenoids?
I will add no additional codes have popped up yet, even though it drives so poor. The Short term and long term fuel trim appear to be within range as do the O2 sensors.
My wife and I have been car pooling all week in the VR, but I need to get the XC90 back on the road ASAP
Thank you for your help!