01 XKR Hesitation during acceleration
 

During heavy acceleration (normally around 2700 rpm) motor begins to hesitate significantly and i have to let off on acellerator and then reapply presuure slowly.

I have had only one code show up P0172 which is System too rich bank 1. This has only shown up once and has been cleared but and problem still persists.

Any thoughts on how to solve this one?
Thx

Does the acceleration issue show up at any other RPM band or just around 2,700rpm? I'm not super familiar with my XKR yet (god willing I will never be, hahaha), but if it's just in one spot, I think you can eliminate a lot of stuff.

2,700rpm is pretty low for hard acceleration so I'm guessing this is just right off the line. 1st gear or 2nd gear? My XKR launches in 2nd most of the time, unless I'm hard on it or have sport mode enabled.

By hard acceleration i mean you press almost or to the floor, and it starts to hesitate going up thru 2700 rpm. Codes reappeared today, and i have 2: sytem 1 bank rich and system 2 bank rich. Hmmmm

01 XKR P172 and P175 Codes
 

I am getting both these code which indicate "bank too rich bank 1, and and on 2. The car also hestates bably during heavy acceleration. Any suggestions would be appreciated.
thx

tahoe, welcome to the forums! I see you jumped right in! (Do try to stop by the New Member area and post a casual introduction about you and your car, so you can be properly greeted by more than just me. :)

As for your banks lean, first one bank, now both...I can recommend one or two things.

I too had a single bank error, but it was lean. Since it wasn't both banks, I figured it wasn't an air leak, as that would affect both banks...so I went straight to the mass air flow sensor. After a proper cleaning of the sensors (and the little heating wire) that simple cleaning corrected the problem permanently. Since you are experiencing the same, except on the rich side, I suggest a cleaning there.

Also, air...your car needs it. Drop $15 for a new paper air filter, get that factor out of the way. Make sure when you change the filter, there are no restrictions into the air pipe, into the MAFs, etc...you know, like a leaf that made it by the filter. I removed my entire air pipe (not the air box) and washed it out in the kitchen sink. Dried, then reinstalled.

Also, clean your throttle body. Use specified cleaner for that (as well as the MAFs, just in case that isn't obvious). If you turn the car to ignition position 2 (do not start) you can put something on the gas pedal and the electronics will open the TB plate, allowing you access inside. Just get a clean rag, and use the TB cleaner on it and wipe as much as you can, get the plate really good and where it seats on the TB.

BTW, in the FAQ thread at the top of this subforum, we have a step by step tutorial provided by one of our esteemed members MrTexasDan. Its a good writeup and tells all you need to know. G'luck, and report back when its done. Don't leave us hangin. :)

This is just about always a mass air flow sensor, do you know someone with another jag 4.0? Doesnt have to be supercharged. 1 connector and 2 screws, swap out the mafs and if it changes charectoristics or runs fine now you just confirmed the part needed. Be sure and do a hard battery reset after you fix it to clear out fueling adaptations learned in the ecu

Whats a hard battery reset if i may ask?

Disconnect negative cable from battery and touch to positive to discharge volatile memory in control module...just like unplugging your modem from the wall

The hard battery reset....do you just breifly touch the negative terminal too positive. ? How long shud it touch fro?
thx

about 3 seconds...just enough to discharge all remaining power

Hard Discharge?
 

Wait..haven't heard of this before. So when you touch the negative cable to the positive for a few seconds...both cables have been disconnected from the battery ..right? I mean you don't touch the negative cable to the positive with the positive still connected to the battery...RIGHT???

I got my new Hi Pres Oil cooler hose this evening and will put it on tomorrow. I'm anticipating something like Restricted Performance or something else to show up even though battery has been disconnected for a few days.

Hope to get a response beforehand so I know what to do.:icon_hyper:

Positive still connected...no harm will come.

no harm will come? THATS BANNANAS !

Old thread, but the advice is correct, just not stated clearly. The negative post on the battery is disconnected so you are not shorting out the battery. All you are doing is discharging the capacitors in the electronic modules. This is called a hard reset.