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HELP slow acceleration under 4k rpm

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Old 10-19-2009, 06:28 PM
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Default HELP slow acceleration under 4k rpm

Hey guys, just noticed that when i hit the gas pedal there is a lag to accelerate anything under 4k rpm and after that it feels like the motor kicks in finally. i have 152k miles on my car regularly oil changed and regular maintenance with all the fluids. i did recently changed my tranny fluid. my thought is there may not be enough tranny fluid that is causing this delay when i accelerate. even when i go full throttle i can feel a lag. idk what the problem is. any suggestions?
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Old 10-19-2009, 06:45 PM
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Spark Plugs???
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Old 10-19-2009, 07:12 PM
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^ Regular maintenance would call for plugs to be changed at 120k miles, so he should have already done that. IF not, then sure, time to change them.
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Old 10-19-2009, 07:44 PM
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my guess was the sparkplugs as well. good luck
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Old 10-19-2009, 07:45 PM
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did you clean the MAF sensor?
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Old 10-19-2009, 08:13 PM
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i'll change my spark plugs today after work. thx. i do remember changing them 20k miles ago and i'm sure i should have changed them again since. thx
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Old 10-19-2009, 08:13 PM
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btw, shouldn't have anything to do with the tranny fluid either right?
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Old 10-19-2009, 09:24 PM
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I would say MAF or plugs... go clean the maf first... that doesnt fix it check your plugs
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Old 10-19-2009, 09:24 PM
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lol nothing to do with trans fluid....but yea my money is on the plugs...unless ur runnign iridium(which last about 90k) then change ur plugs every other oil change....also a dirty maf could also cause this
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Old 10-20-2009, 06:14 AM
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lol while you've got the hood up and are changing the plugs, you could also slap a decent turbo/intercooler setup on, that would also help the slow acceleration
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Old 10-20-2009, 06:30 AM
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Bad O2 in my book. MAF sensors don't usually get messed up unless tampered with. A little cleaning wouldn't hurt it but if it's as sluggish as he says it is, it is probably a faulty upstream O2.
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Old 10-20-2009, 12:45 PM
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Originally Posted by rangerryda
Bad O2 in my book. MAF sensors don't usually get messed up unless tampered with. A little cleaning wouldn't hurt it but if it's as sluggish as he says it is, it is probably a faulty upstream O2.

but a faulty upstream would yeild a check engine....."when the light comes on, just come in......pepboys do everything for lesss LOL" song stuck n my head
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Old 10-20-2009, 04:11 PM
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A bad MAF would also throw a code. MAF Circuit - Voltage Too Low/High would pop up.
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Old 10-20-2009, 06:35 PM
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Originally Posted by rangerryda
A bad MAF would also throw a code. MAF Circuit - Voltage Too Low/High would pop up.
ive had 2 mafs take a crap on me one never threw any codes..
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Old 10-21-2009, 12:15 AM
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Few things affect low speed performance other than plugs. With moderate throttle you can have low intake vacuum = heavy engine loading which can affect plug performance (misfires) more than a higher rev with lighter throttle. But checking the plugs will show you any other problems with combustion as well - fouling, incorrect gap, wear etc. so checking them first is usually a good idea. Next thing could be the VVTi timing of the valves being stuck, then less likely is A/F ratio which could be affected by the O2 sensor and the MAF sensor.
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Old 10-23-2009, 09:31 PM
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lol thx for the suggestions. no cel codes. just bought some new spark plugs today. gonna put em on after work. i'll let you guys know what's up. thx
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Old 10-23-2009, 09:42 PM
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Whats the best spark plugs and plug wires too use
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Old 10-23-2009, 11:15 PM
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NGK Iridum plugs seem to be the plug with very good results. You don't have wires anymore - the coils are right on top of the plugs.

Check your old plugs for fouling and excessive gap as you take each one out and note if anything looks "funny" on them and what cylinder they came out of. You should also take a look at your tail pipe and see if anything is building up in it like soot or oil.
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Old 10-23-2009, 11:26 PM
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Originally Posted by egscion
i'll change my spark plugs today after work. thx. i do remember changing them 20k miles ago and i'm sure i should have changed them again since. thx
If you changed them 20k ago then you should not have changed them since, especially if you used iridium like comes in the car. Those are recommended for change in 120,000 miles.

And a MAF sensor should be cleaned somewhat regularly. I clean mine every 2-3 oil changes. If they get cruddy, then performance can suffer, even without any codes being thrown.
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Old 10-24-2009, 01:33 AM
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Is there any better coils than the oem ones?
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