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This 5MT DOHC EJ25 OB is actually a low miles sub... about 140K. I helped the owner put new intake valves in it and it has been running just fine (like a swiss watch) until today. We installed a new timing belt and those pricey six-star HG's. It also has a brand new fuel pump that we installed last year. I know the owner put plenty of miles on it during the past ten days. It started bucking slightly yesterday on the freeway but it has gotten much worse. Presently it will idle o.k. but if you jab the throttle fast it just goes BLAHH and almost dies. So what could it possibly be? Any educated guess would be appreciated. Also; why would the title say it's a 99 when the manf. date on the door says 8/98? Isn't the cut off date/month normally Sept?

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Next model year vehicles often start being built in May or June. Generally they don't release until August or September, but they can release the next model year as soon as January 1st of the previous year. (Release a 2010 model on Jan. 1, 2009)

 

Low fuel pressure comes to mind. But check all the simple stuff first. Vacuum hoses, and all of the hoses that attach to the intake tube.

Make sure the plug wires are all fully seated (clicked). Double check any wire harness connectors you had undone to do the engine work.

 

X2 on checking timing. The tensioners on those engines are known to fail if they're re-used. Timing could have jumped.

Edited by Fairtax4me
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He already ran to the parts store and bought a fuel filter, new coil, and plug wires. He likes to throw money at it apparently?  I'll put that stuff on tomorrow but personally I tend to gravitate toward the skipped timing belt scenario like you suggest.  He said he had it scanned earlier today and that #1 and #2 were misfiring.

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 #1 and #2 were misfiring.

 

this would suggest a coil or igniter issue.

timing would / could cause misfires on the same side, 1 & 3 or 2 & 4.

 

since he bought the coil , install it.

but if that does not fix it it could still be the igniter.

it feeds the coil in the same way the coil fires the plugs, front vs. rear.

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I put the coil and new fuel filter on and it seems to have cured the problem about 95 percent but it still cuts out (with the pedal to the metal) around 5K RPM like it isn't getting enough fuel. I haven't put the new plug wires on yet but I'll get to that tonight. Question; the small plastic nipple on the purge solenoid that gets vacuum from the top of the intake was snapped off at some point so we plugged the vac line going to it. Could that maybe be a factor with the current issue ? see pic.

Edited by darsdoug
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I had the same symptoms in my 2004 Forester a little over a month ago.

 

I went for the fuel filter first. Didn't help.

 

Check the codes for my CEL (it's always on due to an evap leak, so I didn't know it was throwing new codes) turns out the terrible bucking was the engine misfiring under load.

 

I went to pull spark plugs to do a little diagnosis and the rubber hood on the first plug was soaked with oil. My head gasket was leaking oil internally and causing my misfires. I got the HG's done on the engine and it has been perfect ever since.

 

Maybe the HG job wasn't perfect and it is leaking internally?

 

(Edit: Just tweaked some wording.)

Edited by jmoss5723
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Changed the plug wires a few minutes ago and it's still having same problem. The old wires didn't have any oil on em. Right now I'm guessing a bad igniter on the firewall or bad gas? Contaminated fuel is exactly what it is acting like. I took a sample from the fuel line but it appears clear. A big tall pounder of it in fact. Could it be a crank or cam sensor? I'm not getting a check engine light. :wacko:

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