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2002 olds Alero 3400 "Loss of power over 4k rpm's


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Triklem
New User

Mar 23, 2011, 7:12 AM

Post #1 of 5 (6210 views)
2002 olds Alero 3400 "Loss of power over 4k rpm's Sign In

Ok, Just so u all know, i have done Auto repair in the past and this one is just dumb founding me.

Here is the problem. I have power all the way upto 4k rpms. as soon as the need on the tack hits 4k rpms i loose all power from the motor (loss of speed if going up a hill, will barely hold stable on a flat road). i started noticeing the problem about 2 weeks ago and it hasnt gotten better or worse since then. I have changed the spark plugs in it thinking that maybe i had fouled out a plug. After that didnt fix it i then changed out the original spark wires and put in a premiem wire. still didnt fix it. the vehhical has 250+k miles on it. We have had little to no problems with it till this point, just regular maitance of it is all. The service engine light has come on but only for a short time (about a day) and then has stayed off. We changed otu the Oxgen sensor last fall when mileage was starting to drop. i have noticed that it wants to studder/delay in initial acceleration from a dead stop.

i have a thought that it maybe the calalitic coverter plugging up or maybe the fuel pump getting weak.

just looking for more thought or ideas of stuff to investigate before this week end when i bring it to my buddys shop to rip into it. Since the engine light is not activly on i doubt we will pull a code. it doesnt seem like a missfireing issue since it does not actually run rough or spit or spudder un less its over the 4krpm and even then it still seems to be running fine just no power at the wheels or accelerator (meanign that if i give it more gas it actually runs worse like u are over loading the motor with fuel). I dont think it would be the fuel pump and can get a reading on it after this week end.

Just looking for ideas that maybe i have overlooked or just plain frank havent thought of.


thanks for any input in advance


Hammer Time
Ultimate Carjunky / Moderator
Hammer Time profile image

Mar 23, 2011, 7:46 AM

Post #2 of 5 (6203 views)
Re: 2002 olds Alero 3400 "Loss of power over 4k rpm's Sign In

If the car has over 250K, why on earth are you revving it past 4000RPMs? You're probably pretty lucky that it hasn't come apart already.

You can easily rig up a fuel pressure gauge to monitor fuel pressure during the failure to see if it's fuel related.



~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



Triklem
New User

Mar 23, 2011, 8:43 AM

Post #3 of 5 (6198 views)
Re: 2002 olds Alero 3400 "Loss of power over 4k rpm's Sign In

Mainly when u go to kick it down to pass or go up hills it kicks it down and the rpms are going over 4k. I will be testing the fuel this weekend to see if that is the issue. i am thinking that it maybe needs a new one specially with the miles that it has on it and never haveing a issue with it. thanks for the responce.


Hammer Time
Ultimate Carjunky / Moderator
Hammer Time profile image

Mar 23, 2011, 8:49 AM

Post #4 of 5 (6195 views)
Re: 2002 olds Alero 3400 "Loss of power over 4k rpm's Sign In





~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



Triklem
New User

Mar 29, 2011, 10:57 PM

Post #5 of 5 (6177 views)
Re: 2002 olds Alero 3400 "Loss of power over 4k rpm's Sign In

Ok, after a day of diagnostics and trouble shooting...

came up with codes p0404 and p0300

404 i believe was the misfire code and p0300 was a EGR valve failure.

So just replaced the EGR the misfire was next.

So we checked out the MAF and Fuel pressure. MAF was fine and Fuel pressure was 57 KOEO and about 50 psi at idle spike to 56-58 when reved.

and the issue about power was still there. so after raodtesting a bit and seeing that the transmision wasnt shifting. raised a few new questions. So took it back and started tinkering. was thinking maybe the kickdown sensor(term) was failing to tell the tranny to shift. After a few quick calls to see about parts and cost, we desided for SNG's that we would take out the oxygen sensor and see if by chance it would act any differant. Come to find out the catalytic converter was in fact plugged. so a few more calls and a trip to the part store we had solved all the issues. Transition is nice and solid now, runs nice and smooth. can even get to 60 in a short time if needed now.

Runs better now then it did at 50k miles. LoL

thanks for the stats on the fuel pressure. Problem is solved






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