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Old 06-14-2014, 01:32 AM   #1
klaus_b2
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Default sluggish 2.5, why?

long story short, lately i have been noticing my car (07 2.5i) has lost some power. Some problems im noticing is that around 3.5-4k rpm itll "lag" and it definitely doesnt have as much "pick up" as it used to. Also, when i start the car when its warm, it tends to almost stall out. sometimes, the rpms even hit 0 but it the car doesnt stall. so im thinking its a fuel issue? theres no dents/holes/damage in the exhaust either. so I was gonna start with the cheapest solution being the fuel filter possibly? just wondering if anyone has had this problem, or know what the problem is? any help would be appreciated. AND ive cleaned the maf and throttle body.
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Last edited by klaus_b2; 06-14-2014 at 01:40 AM.
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Old 06-14-2014, 03:13 AM   #2
Ismokeyou
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Have an 06 with the same issues, in for more. Mainly have the starting issue
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Old 06-16-2014, 08:34 AM   #3
GTR Fever
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when last were the plugs changed? Can look at the plug wires/ coil packs and fuel system...the in-tank filter and engine-bay filter
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Old 06-16-2014, 09:53 AM   #4
cmiovino
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Try cleaning the MAF, or changing the front O2 sensor. Most 2007 models are getting some higher mileage (60k+) and will need to start changing out some of these things.

Plugs are another one around 60k, but usually misfires and other assorted things go wrong when plugs are worn. I'd throw that out for now, but still change if needed.
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Old 06-16-2014, 09:55 AM   #5
woodstocktech
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It wold to find somebody with a scanner and monitor the o2 sensors with the fuel trim. Could be a "lazy" sensor. While youre in there watch cam and crank sensor performace
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Old 06-16-2014, 12:29 PM   #6
klaus_b2
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ive cleaned the maf, i have a borla uel headers and i actually spliced my o2 sensor wires when installing them and ended up ****ing them up so i have 2 new o2 sensors so. and i have to change my spark plugs pretty often. i do them every other oil change or my cel will come on cause of the exhaust.. im still leaning towards a fuel issue? im gonna start on a new fuel filter first i suppose..
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Old 06-16-2014, 09:55 PM   #7
Subie-Lifer
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WTF? Plugs last way longer than that. What codes do you have? Did you get direct fitting O2 sensors?
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Old 06-17-2014, 12:23 PM   #8
klaus_b2
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Quote:
Originally Posted by Subie-Lifer View Post
WTF? Plugs last way longer than that. What codes do you have? Did you get direct fitting O2 sensors?
i dont have any codes.. and yes they do last longer than that i know. im about to be on my 4th oil change since ive replaced them and still havent had a code pop up yet. but when it does pop up, its a p0420.
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Old 06-17-2014, 12:55 PM   #9
trexbob
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Lots of things to try...Is the air filter ok? Got any spare known good plug wires around? If so, try replacing one at a time. Make sure your engine grounds aren't too corroded. Then when your ready to get down to business - check your cylinder compression. That's free and easy, if you have a compression gauge. Then start throwing money at parts you may or may not need... That's what I would try first.

Another thought since you get a P0420 occasionally... your Cat. Converter may be disintegrating and starting to produce too much backpressure. I'd take a look there.
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Old 06-19-2014, 02:15 PM   #10
Pickler
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this is knock. Every 2.5i i have seen either knocks or has a very sensitive knock sensor registering phantom knocks. this causes small learned ignition timing. less power, less fuel economy and higher exhaust gas tempratures.
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Old 06-19-2014, 11:10 PM   #11
klaus_b2
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Quote:
Originally Posted by trexbob View Post
Lots of things to try...Is the air filter ok? Got any spare known good plug wires around? If so, try replacing one at a time. Make sure your engine grounds aren't too corroded. Then when your ready to get down to business - check your cylinder compression. That's free and easy, if you have a compression gauge. Then start throwing money at parts you may or may not need... That's what I would try first.

Another thought since you get a P0420 occasionally... your Cat. Converter may be disintegrating and starting to produce too much backpressure. I'd take a look there.
yeah i was gonna try the compression test as well. but no im sure its not the exhaust. i throw the code because i have the uel headers.. not because of this issue. thanks for the input though

Quote:
Originally Posted by Pickler View Post
this is knock. Every 2.5i i have seen either knocks or has a very sensitive knock sensor registering phantom knocks. this causes small learned ignition timing. less power, less fuel economy and higher exhaust gas tempratures.
so.. replace the knock sensor? haha
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