1999 Cherokee Left Turn Stall (Full Tank) HELP!!

[nysabre]

Recently I have been plagued with numerous problems involving the stalling and sputtering of my 99 XJ 4.0 i6 4wd. After weeks of work I seemed to have isolated a problem when making hard left turns. Every time I attempt to make a left turn from a stop or try to accelerate hard through the turn the engine sputters and acts like it is going to stall. I have read about the 1/4 tank problem from the feeder tube. This however, this occurs with a full tank. The fuel system pressure at the fuel rail is 45psi before start and at 50psi after start. I have cleaned grounds, replaced sensors, filters, and check a lot of wires around the exhaust manifold. This only happens when in gear. I have tried to wiggle wires and things while idling but to no avail. Is there something I am missing? I really need some help on this one. Thanks.

PS. could it have anything to do with a slight rattle in the cat?

[nysabre]

Could it have anything to do with oil leaking onto the spark plugs maybe a bad seal or something of that nature. possibly when turning left the oil washing onto the plugs is causing a misfire? I don't know what else it could be.

I am going to check my plug for oil residue today.

[Saudade]

Does it still clear up once you straighten out? I'd still check the fp inlet.

[fredjacksonsan]

While all the above is certainly possible, it could also be the CPS. How many miles?

[nysabre]

The problem stops when straightening out, almost immediately upon turning the wheel back the other direction. The steering assembly does not appear to pinch or twist anything as it moves independently from any wiring. As long as I don't try to accelerate too hard or am not going up hill turning left it acts fine. Up hill turning right or straight up hill there is absolutely no problem. With a full tank it would seem that the pickup in the tank would be completely covered anyway so shouldn't be the problem.

As far as the CPS goes, it has been replaced within the last 6 months. When this problem started if the engine was not at operating temp it would stutter upon shifting into gear and any attempt at acceleration would cause the vehicle to die. After this event the vehicle would not start. The new CPS immediately solved this problem. This is when I was able to narrow the symptoms down. In addition to the CPS the following has been replaced: Spark plugs, SP wires, Distributor, Dist. cap, rotor ign., battery, TPS, air filter. ~175000 miles

Fuel pump is priming, pressure is good.

The other thing is that when this stalling and sputtering occurs the speedometer needle jumps from whatever speed I am at all the way up and then back down. RPM reads normal.

Thanks for the responses.

[nysabre]

If anyone has any suggestions please help. I'm not sure where else to go.

[fredjacksonsan]

You said you had a rattling in the cat. How bad is it? Can you hear pieces rolling around in there? Check out this thread for info on the catalytic converters...there have been a few problems with that model year, mostly in Dodges but also some Jeeps as well. If the cat is getting blocked by chunks inside, the exhaust restriction could cause what you're experiencing.....which I take to be more of a bogging rather than a miss in the engine.

When did the problem start? Now that you mention the speedo jumping around, I might think a bad CPS could be at fault. Also, the output speed sensors on the transmission could possibly make that happen.

[nysabre]

Problem started around October 2008. The rattle is not very loud but definitely from the cat. The thing is that this only happens in gear, and only when accelerating. If I am in neutral or park, I can rev all day with no trouble. Checked the thread but I am over 120000. Could it have something to do with the flexing of fuel line or something during those turns and hard acceleration. If I try to gun it from a stop going straight it does it too. Could that flexing cause me to loose a vacuum if there is a hairline crack? Thanks

[nysabre]

New Development.
Recently I have noticed that when the front of the vehicle sits higher than the rear of the vehicle, i.e. in a driveway. It will start fine, and I can shift into gear as soon as my foot comes off the brake and I start to move it will sputter and stall. I cannot start it again until the vehicle is level.

[nova73noir]

check engine light is on?

[nysabre]

no there is no engine light.

[nova73noir]

poor or loose connection to the battery or a wire grounding somewere
do you have anti theft system?

[nysabre]

The battery terminal ends look pretty old but seem like their making a good connection. When in idle I try to give them a tug possibly simulating the hard left turn and nothing. I have cleaned all the grounds I could find. It's weird It seems like something is being pinched or pulled but I can't find anything that looks like it would be any where close to getting pinched. The only other thing is that the connection on the starter seems a little sketch but a wiggle of that and nothing in idle. It only seems to happen when moving.

[Saudade]

I still think you need to pull the FP assy out and check the connections.

[ronaldk]

I was leaning towards broken parts in cat or (and this may still be) a wiring fault on o2 sensor but the key is your speedo jumping when prob happens. that makes me think electrical. check batt terms take off clean dont just yank, check grounds. I assume your batt is straped down so cant short in turns? check o2 sensor for bad wires or conn may not code.oh and when you say wouldnt start on hill i would park on hill get it to not start and see whats not there like spark or fuel