Misfiring/Backfiring/Loss of Power/Something

[Ryan L.]

Hey all...

2004 Jeep Liberty Sport 4x4.

So heading out to Anza Borrego today, everythign is fine in the Jeep. Make it about 60 miles, go to pass somebody, Jeep starts backfiring and won't go above 55mph or shift. Check engine light starts flashing so I pull over.

The engine was shaking pretty bad and you could hear the sputtering coming out of the exhaust. Check engine light is still on, solid though not flashing. So I turn it off and disconnect the positive battery just to reset everything.

Start it back up, running a little better, light isn't on but still shaking abnormally. Start driving up and down this side road trying to get the light to come back on, no avail. Floor it and it starts backfiring and again wont go above 55mph.

So I take out all the plugs that go to the coils and blew them out a little and plugged them back in. No change.

What do you think could be wrong? Spark plugs have about 6k on them with no problem, I haven't changed anything in the past month on it and have gone on 100 mile trips with no problems.

The only difference is the gas. I got it at a gas station I normally don't go to and got it early in the morning.

Thanks in advanced.

Ryan

[Alex C.]

Re: Misfiring/Backfiring/Loss of Power/Something

First and foremost, have the codes read. If you don't know anyone locally that has a reader or don't want to deal with mechanics, you can use mine(it's a great tool to have). I'm in West Covina, all it would cost you is your own gas.

[jmakado]

Re: Misfiring/Backfiring/Loss of Power/Something

Fire, fuel, air. Assuming you are having no issues getting air then it's something with the fuel or spark. I'm sure your liberty has a knock sensor so even with questionable gas it should run fine. If it was contaminated gas it *could* clog the fuel filter but it's unlikely. When fuel pumps go they generally just die a fast death and don't throw codes...but it's not impossible.

My guess is a harness or connector either got water in it or came loose. Do a visual on the engine bay and see if anything is loose or not connected. Any chance you rinsed your engine bay recently? It could also be a leak between the air meter (not sure what's on a liberty. Mass airflow sensor maybe?) and the engine, a vacuum leak, etc. Just give everything a good look and give the vacuum lines a tug to see if anything is off. Do you hear any hissing with the engine running? How does it idle?

Your best bet is to find somebody with a scanner and pull the code. Autozone does it for free I think. It's pretty tough to guess what could be wrong without knowing more or seeing it in person.

[Eddie6th]

Re: Misfiring/Backfiring/Loss of Power/Something

could be a lot of things.I agree with black,go to the dealer and get the codes read,unless you know how to DIY.

I'm not familiar with this particular vehicle.Is it a turbo diesel?

[Tim Lingor]

Re: Misfiring/Backfiring/Loss of Power/Something

Hey Ryan,

That could be a lot of things from a camshaft position sensor (but usually it will idle fine if it is that sensor), plugged fuel filter, bad coil, to a failing fuel pump (normally like Jason said, they just die. However, I have seen some which started to fail causing hard starting and stalling when engaging the clutch). Have you washed the engine lately by chance?

You definitely need to read the codes as otherwise you could be searching for days. But if you have not changed the fuel filter in a while, I would consider doing that...

Tim

[Bounty]

Re: Misfiring/Backfiring/Loss of Power/Something

The only difference is the gas. I got it at a gas station I normally don't go to and got it early in the morning.

Always a possibility. Although, like the others, I'd recommend clearing the codes first you could try an octane booster/fuel system cleaner in case you did get some contaminated/poorer quality gasoline.

[Eddie6th]

Re: Misfiring/Backfiring/Loss of Power/Something

Always a possibility. Although, like the others, I'd recommend clearing the codes first you could try an octane booster/fuel system cleaner in case you did get some contaminated/poorer quality gasoline.

Hi Bounty,while you were talking about fuel.What is the standard RON in the states.Is it the same as over here 96?or is 92?

[ColonelCash]

Re: Misfiring/Backfiring/Loss of Power/Something

Hi Bounty,while you were talking about fuel.What is the standard RON in the states.Is it the same as over here 96?or is 92?

If you are talking about octane, it's 87 (low grade) 89 (midgrade) and 92(premium).

[jmakado]

Re: Misfiring/Backfiring/Loss of Power/Something

We don't use RON like in Europe. We use an average of RON and MON called AKI to come up with our "octane" numbers listed on the pumps. So your 96 is about like our 91.

[Eddie6th]

Re: Misfiring/Backfiring/Loss of Power/Something

We don't use RON like in Europe. We use an average of RON and MON called AKI to come up with our "octane" numbers listed on the pumps. So your 96 is about like our 91.

Ah,thanks for that explanation.I was wondering 92 premium? So 91 = 96.

We get three types here:

96 Standard
98 Agip(Ithink?)
100 Shell V-Power

I can't afford to use the V-power all the time!

I was told that in Japan the standard is 99/100. Don't know if that's true?Some one here will know,i'm sure.

[jmakado]

Re: Misfiring/Backfiring/Loss of Power/Something

Japan also uses RON only for their numbers. I *think* that north America is the only place that operates on the RON/MON standard. 100RON is around 95 at American pumps.

[roushstage2]

Re: Misfiring/Backfiring/Loss of Power/Something

A CEL indicates some sort of emissions equipment failure. Generally speaking, something like that will make the vehicle go into some sort of "safe" or "limp" mode. Get those codes.

[Nappers]

Re: Misfiring/Backfiring/Loss of Power/Something

I agree, get the codes, Schucks/Checker, Autozone etc should have code readers then once you get the code, post back here or google it.

Like Tim said, could be a ton of things, cam position gizmo, engine control module of some sort, plugged fuel line etc.

Keep us posted!

[Alex C.]

Re: Misfiring/Backfiring/Loss of Power/Something

Do the parts stores still rent out code readers? I tried about a year ago, before i got my own, and they said there was a new law saying that they couldn't rent them out anymore. Something about repair shops/mechanics getting their undies in a bunch because parts stores were offering the service for free. Sounded greedy enough to be true.

[Ryan L.]

Re: Misfiring/Backfiring/Loss of Power/Something

It's at the dealer right now and its throwing a P0300 code.

What a P0300 Code is: Random/Multiple Cylinder Misfire Detected. I guess if its a P0301 then it would be cylinder 1 but a 0 at the end indicates any one of the cylinders, it could be just one or all or anything in between.

They have nothing else to tell me other than that but everybody I've asked is leaning towards bad gas or a leak in the EGR.

Hopefully they will be able to pinpoint it tomorrow and start working on getting it fixed. The main problem is that because it is not saying one specific cylinder, there can be a bunch of other problems leading up to it.

Thanks for the help guys.

Ryan

Edit: The reason we took it straight to the dealer was because we bought the best warranty out there when we bought it and it basically covers basically everything for $100 detuctible. We got a new transmission, transfer case, torque converter and rear axle from the $100 deductible.