gregrichardson

Have a 2003 grand Cherokee 2.7 CRD. Sometimes wen I select reverse or drive first thing in the morning it seems to lack power. Is this a common problem and does anybody know what the fault maybe? The engine management light comes on and goes off now and again.
Thanks

99 Purple XJ

If the light is coming on then scan it and see what codes its throwing

Zack92MJ

x2

BrofessorXJ

Had a similar problem and it turned out to be a cracked exhaust manifold and bad upstream o2 sensor.

gregrichardson

Was it an easy fix? How much did it cost?

BrofessorXJ

O2 sensor is an easy fix a new header is not.

O2 sensor is as easy as just unplug, unscrew, plug in the new one and screw it into the downpipe.

Replacing the header is a rather big job you have to take out your airbox or aftermarket short ram whatever you have, remove the throttle body and all cables and sensors attached to it, remove the fuel rail, remove all vacuum lines and sensors on the intake manifold, unbolt the power steering pump, unbolt the top bolts on the intake manifold, remove the PITA bolts under the header, remove intake manifold, disconnect your old header from the downpipe collector, remove old header. That is what I had to do on my 4.0

My symptoms were when I start it up in the morning or after it had been sitting for a while I would gas it in drive and it would kind of bog down then I would let off the gas and gas it again and it would be fine until next restart. Turns out I had a bad o2 and the cracked header was causing my o2 to go bad but wasn't throwing any codes because it wasn't stuck rich or lean.

Here's my quick solution:
Disconnect your downpipe from your exhaust header and see if you have the same problem. Make sure you use PB blaster on the bolts because they like to break. If you do not have the same problem after the disconnect, then you know it's a bad o2, cracked header, or a clogged cat.

Or if you are throwing codes get it read.

Good luck.