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Sputtering/ backfire at idle/ low RPM now won't start

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Old 12-29-2014, 03:27 PM
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Default Sputtering/ backfire at idle/ low RPM now won't start

Wow, so it's been ages since I posted on here!

Ok, so as the thread title indicates, I'm having an issue that's changed some over the past month. Apologies in advance for the length of this post.

About a month ago, I noticed that my 2005 xB (157,xxx mi) was making kind of a percussive "puff" noise at idle, mainly after the car had warmed up. I work for a Toyota supplier, so I hoped to just limp it along until winter shutdown when I could run it by a shop to take a look at it. To date, I've not thrown a code or had my CEL activate.

Over the past month, the puffing has gotten a little worse, not in the volume or frequency of the puff/ popping, but in that it started doing it not just when I was idling at a red light, it started doing it at low RPMs when I was on the highway too.

I was due for an oil change anyway, but the oil change place i use isn't really a full-on mechanics shop, so I didn't bother mentioning the problem to them. Oil change had no effect. This was three weeks ago or so.

Around that same time, just after the puffing/ popping started (hesitate to call it a backfire because it's not like a loud crack, just kind of a percussive sound), I hit something in the road. I don't know if it was a roll of carpet or big animal or what- it was raining, there was traffic in the oncoming lane, I couldn't stop before I was on it. My xB is lowered, so I felt it hit the front and the back, kept on going as I was already late for work. End result is it separated my back airdam. Not sure if this is related in any way to my issue, it seemed to have no effect, but in the interest of full disclosure, I thought I'd mention it.

Did some Googling for rough idle and saw that it might be the PCV valve. Stopped by parts store and picked one up on the 22nd. Replaced it, no effect. The old one did seem bad however, as it rattled when I shook it, which according to what I read is an indicator of it being faulty.

The wife drove the xB to work on Christmas Eve so I could take our kids by my folks place as we only have car seats in her Jeep. It made it to her work and back with no issue though her commute is only about 7 minutes whereas mine is about 35.

Anyway, no driving on Christmas Day, but the day after, I needed to run to the store and it wouldn't start. Starter works, engine cranks, but it never turns over. To me, and maybe it's my own bias, but it sounds as though it's doing the puffing/ popping when I'm trying to start it up now. Up until the 26th, I never had an issue with it starting- I have to park outside at work and it took a little longer to turn over, but I assumed that was because of the cold weather rather than an actual issue with the vehicle. And when I say it took longer to turn over, I'm saying I had to hold the key for maybe an additional second- I didn't turn it, have the engine not turn, then turn the key again. It still started up on the first key turn, just had to hold it a bit longer.

Anyway, I figured I was due to clean up the SRI air filter and read some threads on here about cleaning out the pipe, throttle body, and idle control valve, so I did that. Sprayed down the MAF sensor too. I was also due for some new spark plugs, so I put those on as well. Got everything all zipped back up, no change- still won't turn over and start running.

Called a buddy of mine who used to run his own garage. He suggested fuel filter/ fuel pump. Ran by parts store, they had the pump but not the filter. Installed the pump last night late, no change whatsoever. I guess it's possible it could be the filter is so clogged that even the new pump can't push anything through it, but as this has been kind of a gradual problem, I find that hard to believe, frankly. Unfortunately, it didn't occur to me to try and listen for the pump running before I replaced it, but I definitely do hear it running now that I'm listening for it.

So any thoughts? I'm the only owner of the vehicle and being as how it's been paid off for years, I'd really like to get it running again and wouldn't mind spending a little dough in the process if that's what it takes. Just kind of out of ideas at the moment. I guess I could do some looking for a fuel filter, but like I said, I'm not really all that convinced that's the issue.

TL;DR- 2005 xB won't start, isn't throwing codes, been idling kinda rough in the month or so leading up to this point.

Thanks guys!
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Old 01-02-2015, 08:56 PM
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Are your plugs and coils good?
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Old 01-02-2015, 10:37 PM
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Try a compression test. That will tell you if you have a bad engine valve or not.

The PCV valve is supposed to rattle BTW
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Old 01-05-2015, 03:44 PM
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Originally Posted by Godfryness View Post
Are your plugs and coils good?
Nope. Turned out I had a bad coil pack on cylinder 4.

Mechanic said the only thing he could figure was that it wasn't misfiring often or for long enough to actually set off the CEL. Changed out the coil pack, immediately got better, but was still puffing some. He said it was possible that the injector was dirty from the misfires and to run a fuel system cleaner through the gas the next two tanks. Put one in last Saturday, haven't had the puffing since!
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Old 01-05-2015, 03:45 PM
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Originally Posted by RichBinAZ View Post
Try a compression test. That will tell you if you have a bad engine valve or not.

The PCV valve is supposed to rattle BTW
Ha, yeah, that's what the mechanic told me as well. I either read that wrong when I found the thread on replacing the PCV valve or the guy actually wrote it wrong. Either way, I think it was only $5, so I'm not that torn up about it.
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