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Help Me! Please Read! Video Included!

12K views 78 replies 22 participants last post by  CPT2010 
#1 ·
My WK started bucking really bad after I had a mechanic look at it. I noticed that he pulled a vacuum line while it was running.

After he looked at it, the check engine light was on but I didn't pay it any attention. After driving it for a while, the engine light began to flash and that when I started to worry.

I then noticed that when I accelerate heavily, I get very bad surging/bucking at around 40mpg @ 3,000rpm.

I checked the hoses. They are connected. He only pulled on hose and immediately put it back on.

You will get a very good look at it towards the end of the video.

 
#2 ·
It's having hard time cranking now.
 
#8 ·
That's exactly what code P0300 is. I'm at Advance Auto right now with the machine. They give it to you to use in the parking lot for free. :lol:
 
#7 ·
Got the codes.

P0339
P0300

Funny thing is that it's not doing it anymore. The engine light is still on but it's not in flash mod anymore (it's not continuously flashing like it was when I had the problem).
 
#11 ·
I cleared the code with the machine already.

What do you think is was Acid?

I shouldn't have that problem even if the guy pulled the vacuum line while it was running.

Could I have a vacuum leak somewhere?

WTF? Lol.

The CEL is gone and it hasn't come back.
 
#12 ·
Wait.....I'm currently driving down the road and it's doing it again. But no CEL. WTF!
 
#14 ·
Yes. I was watching.
 
#15 ·
Ok. It's not doing it now.

Anybody have any idea what's going on????
 
#16 ·
Could a vacuum leak cause this?

When he pulled the vacuum line while it was running, it bogged a little and that's when this all started.
 
#17 · (Edited)
It's the anti seat belt engine lock out. Put your seat belt on and it'll all go away......

jk, Have you checked your coil packs and made sure all the connectors are nice and tight? Why were you at the shop to begin with?

You said: "My WK started bucking really bad after I had a mechanic look at it".

What was it doing that made you take it to the mechanic to begin with? I'm wondering if we're only getting 50% of the story here :)
 
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#18 ·
I wanted to see if I needed manifold gaskets. We were looking for a source for my slight tick and he noticed a slight hissing sound. That's when he checked the vacuum line.

Come to find out, I have no exhaust leak because there isn't any black residue anywhere around the gaskets.
 
#19 ·
I think you're out of gas.... it's on E... haha kidding sorry

Can we look up these codes for him? I'm going to google...
 
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#20 ·
Well if ya go to the trusty ol Air/Fuel/Spark.... Im guessing if his codes are showing a misfire i'd check plugs, ignition coils. Im not sure how you'd check the actual fuel. Any chance someone put water or something else in your gas tank?
 
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#21 ·
P0339 is the crankshaft position, so look for that sensor and make sure it's secure.

P0300 is multiple cylander misfire.

Sounds to me like your mechanic can't keep his hands off wires. betchya he was tugging. Go make sure every wire on the coil packs is secure, and all your wire connectors are secure.

The intermittent issue is probably because they are loose but not completely un done.... so they might be working one minute, then after a bump, not.
 
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#31 ·
x2

The crankshaft position sensor is used by the PCM to determine proper timing. So my guess is if the connection keeps going in and out the PCM will have trouble getting the timing right hence the misfires. If the sensor itself is bad it can cause those issues too. When the sensor went out on my BMW it wouldn't even start.
 

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#24 ·
The guy in that link was think it was the battery.

I do have very little corrosion on the + terminal that just started to happen.

I think I might buy a red top Optima tomorrow. It's what the guys at Advance Auto suggested because the yellow tops they have on the shelf have too little cranking amps. The red tops they have in stock have a little more cranking amps than stock.
 
#27 ·
Not sure. But I do know that he unplugged a vacuum line. A picture of what he unplugged coming soon.

did you go out there and check the wiring like i said up top? Voltage issues will throw another type of code...
I checked everything. Hoses and all.
 
#26 ·
did you go out there and check the wiring like i said up top? Voltage issues will throw another type of code...
 
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#30 ·
But it currently not having an issue. I'm trying to figure out what caused it and worried if it will return.

If the sensor is blown, will it still operate normally?

By the way, thanks for all your help people.
 
#29 ·
He unplugged one of these hoses and the engine bogged and went kinda crazy for a second.

 
#32 ·
My wife's 3.7L Laredo was bucking like that...running like crap. I changed the plugs and it cleared it right up. Good luck figuring it out man. My XJ did that once too and I believe it was bad gas. I know a lot of people don't believe in not running the tank dry, but it can't hurt to fill it up and see if the problem goes away. There could be sediment at the bottom of the tank, or you could have gotten moisture in the tank and with it almost empty, any moisture would be now getting sucked in by the fuel pump. Water floats on gas...
 
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