Bogging out randomly when first starting up

[Dracitamo]

I replaced the fuel pump assembly last year. Recently replaced the TPS and CPS (new parts). Replaced all the spark plugs and rotor and wires. Last night I installed a  new Yellow Top!

I was getting an O2 sensor code so I ran the codes at AutoValue and they told me it was my upstream sensor. I replaced it, but the new wires on the sensor was about 3 inches shorter then the original one. I made it fit, but the wires are pretty tight.   Still was getting the code error. Figure maybe the wiring somewhere up top? I continued to drive and the CEL was still on. Then one day I was driving and it conked out but I was moving so I was still able to keep moving. The dash flashed a couple times and went back to driving like normal. This time the CEL is off. It hasn't come back on yet. The old battery was venting pretty bad so I replaced it with a new Yellow Top last night.

Issue: When I start it up, it's a little rough, when I first start driving its sluggish and bogs down and acts like it's being flooded or not getting fuel. Sometimes it lasts for 10 minutes, even longer when it's colder out. I let it warm up before I start driving but just idling when it's warming up it bogs down a bit and then the engine revs up and comes back down to normal. I've put some fuel injector cleaner into the tank a few times and water remover. Don't know any other simple tests to do. The CEL is currently off so I can't run any codes on it. Waiting for them to come back.


Things to still try: Pull the tank and check the fuel filter in case I got some bad gas? Check the wires on the 02 sensor and check for continuity?

Any other ideas or suggestions?

[Vinman]

Check the ground wire connections between the battery, engine and body. Also check the air filter and make sure it's not plugged up.

Good luck
Vince

[jeepjones]

And the problem was?

[BUKI]

Check vacume. More so on MAF sensor vehicles will throw lean mixture code.  Or cracked exhaust manifold would lean out but not to much. I would check your MAPs output voltage as this could really make an engine act weird

[Dracitamo]

I haven't had the time to work on it as work has been insane before the Christmas break but I will check all these options here soon. Thanks again for all your input and ideas to check.

The CEL came back on finally so I'm going to get the codes ran and find out what O2 sensor is triggering it. Could it be that the new O2 sensor with the wires that are 3 inches shorter then the original be the wrong one?  (I have the old one still just in case so I can take them both in to AutoValue). The guy at the desk said they can have different lengths of wires but It's a super tight fit with no room for play.

[Dracitamo]

I think I figured it out. There is a short or open or high resistance in wiring harness or harness connectors. (CEL finally came back on and I was able to get the codes ran)
I'll give this a shot once I can find the parts. AutoValue and PartSource both recommended I go to the dealership. I'm guessing $$$...
If it doesn't fix it, I'll post back here when I figure it out, but for now, let's cross our fingers that's all the problem is.

[frenchy]

What code # are you getting?
"short or open or high resistance in wiring harness or harness connectors"  This is referring to the O2 sensor wiring, correct?
Not the complete engine bay wiring harness you are looking for in your other post, or is that for another issue?

When you stretched the crap out of the O2 wire, did you perhaps loosen up one of the connectors, or rip wire?

I'd hate to see you go through all that time and $$ replacing a harness and ending up with the same problem.

If you want to replace the complete harness, first unplug the harness and inspect it.
Is it full of corrosion and needs to be replaced?
Chafed or broken wires?
Broken or loose pins? Connector at computer packed with dirt?

Also, Disconnect your Neg. batt. cable for a few minutes, then re test, is it still "bogging out"? Have you tried this also with the O2 sensor not plugged in, still "bogging out"?

[jeepjones]

I'm really interested with what you find is doing this. My Jeep will bog out every once in a long while but it only does it for a few seconds, no CEL ever comes up & no codes at all are ever present. I've done everything I can think of to remedy the ultra random occasion that it happens. I've had the engine scanned while running, replaced the O2 sensors, I know the cat is good, the MAP,IAC & TPS are all good as well as the entire throttle body and Intake/Exhaust systems. The ignition system is also in tip top shape as well as the fuel delivery system. I've run out of idea's, even the shop I have taken it to says to just run it until something rears it's ugly head, then we will have something to look at, not the answer I was looking for.  Good luck and keep us posted.

[Dracitamo]

I got the code: P0135 and yes it's for the O2 sensor wiring, but I just replaced the sensor so it's something in the harness. I hate electrical so I thought it would be easier to just replace the whole harness. Eliminate any future problems that might be coming up with it getting older.
I didn't stretch it too bad that I would have loosened the connectors or rip a wire. I just pulled it snug but there isn't any room for play.

I'll pull the harness this weekend and check the harness for all the things you mentioned. (It would be awesome if that's all it was)

I've disconnected the neg battery terminal a few times after replacing the battery and fixing the starter. When I get the codes cleared it runs fine for 30 seconds and then "bogs" really bad... If I'm driving it kinda lurches and I pull over to let the idling sort itself out (wait about 5 to 10 minutes). Its only in the first half hour that it acts this way. Usually anyway. I haven't done this with the O2 sensor not plugged in. I can try that tonight when I get home.

[jeepjones]

Is it the sensor on the the exhaust manifold? If it is your going to want to have a bit of slack in it for when your hard on the throttle wheelin or just driving in the city because the engine will flex in the motor mounts under torque. If there is no slack it will end up ruining the wiring/sensor. Also another thing to keep in mind is the fact that just because it is a new sensor it doesn't mean it is good. I bought one brand new, put it in and found it was no good straight out of the box. I've also heard (never had to deal with it myself) that Bosch O2 sensors are crap/they don't work very  well in Jeeps. This last piece of info is just something I've read more than a few times on different forums over the years.

[jeepjones]

Did you get it figured out?

[birdo]

I wonder if that after market O2 sensor is causing the grief? First off, having the wires come up short like that indicates that the sensor was the wrong one. Secondly, get OEM sensors from Jeep.  Bosch are crap as I discovered and my OEMs are doing the job, plus the wires  and connectors will be correct. Mine went from a horrible bucking and snorting mess to an engine that now runs smooth as silk. O2 sensors can make a big difference.

[binare]

If anything... the OEM ECM and sensors are crap and dont play well with quality parts such as Bosch ;-)

[Vinman]

If anything... the OEM ECM and sensors are crap and dont play well with quality parts such as Bosch ;-)

Funny you say that, I was under the impression the Bosch sensors are crap

[birdo]

Don't really want to start an argument...can only speak from experience. Replaced my original OEM with a Bosch sensor....about 100 kms later all my engine symptoms returned. Replaced with an OEM and it's been fine ever since....close to a year now. Just saying.......