Problem with my ST!, HELP NEEDED Options

[j0ch0a94ST]

So I've got this issue with my car. It drives relatively normal up to ~ 3500RPM or so and then there is a major drop off in power. Accelerating feels compromised. I though I may be having issues with o2 readings so I checked the sensors today. I unplugged the sensor on the back of the motor and have no check engine light. I know that the sensor used to throw a code when it was unplugged previously. I am still unsure what's causing the power loss. Does this sound spark related to anyone? Thanks for the help.

This post has been edited by j0ch0a94ST: Jan 22, 2011 - 8:24 PM

[4-eyed-freek]

hhmm yes, your plugs could be fouled. does the car stumble a bit after 3500? if so it could be a clogged fuel filter, or an injector issue.
then agian how much of a power drop are we talking about. the 7a isnt the most snappy.

[blu94gt]

I'd vote fuel filter or fuel pump is starting to go bad. Couldn't hurt to do all new spark plugs anyways though.

[Bitter]

timing belt slipped a tooth? bad ignition coil? either are also possible.

[barterj]

Check your cats, when mine went bad, anything after about 3K rpms power was almost non existant

[mgnt232]

All good suggestions. I have my downstream 02 sensor off and it only got a code once, under heavy acceleration with no gas (been unhooked for months).
Just start with this stuff, all besides a timing belt can be fix pretty easily, and relatively cheaply and are all maintenance items that should be replaced on our cars anyhow.
I also have to agree the 7a has never proven much above 3k lol
GL

[j0ch0a94ST]

hhmm yes, your plugs could be fouled. does the car stumble a bit after 3500? if so it could be a clogged fuel filter, or an injector issue.
then agian how much of a power drop are we talking about. the 7a isnt the most snappy.

Sorry guys here's the update on my car. I tested the plug wires and I did have one that was bad and one that was questionable. So I picked up a set of NGK wires for the celi and now its back to operating fairly normal. I don't know if its just me but it still feels like the car is short on power. I bought a fuel filter @ Advance Auto today because it is due but the damn part set me back $20! I've bought a lot of different fuel filters doing tune ups on my friends cars in the past and I've never come across a $20 fuel filter, most of them run 5-7 bucks. Anyway thanks for the help guys , hopefully I'll unlock its full potential soon.

This post has been edited by j0ch0a94ST: Jan 14, 2011 - 9:55 PM

[j0ch0a94ST]

So fuel filter has been replaced. The timing is advanced about as far as it will go and the car operates normally now. We advanced the timing so I could get on the highway without fearing for my life However I want the car to operate properly under factory timing. I have a feeling that it is spark or fuel related. Any help on this would be greatly appreciated. Thanks guys

[HectortheRican]

So fuel filter has been replaced. The timing is advanced about as far as it will go and the car operates normally now. We advanced the timing so I could get on the highway without fearing for my life However I want the car to operate properly under factory timing. I have a feeling that it is spark or fuel related. Any help on this would be greatly appreciated. Thanks guys

How much did you advance it... You're gonna need to always use premium now.

[stephen_lee]

yeah 15-16 btdc is optimum on a stock car.. but use mid grade or better

[j0ch0a94ST]

So fuel filter has been replaced. The timing is advanced about as far as it will go and the car operates normally now. We advanced the timing so I could get on the highway without fearing for my life However I want the car to operate properly under factory timing. I have a feeling that it is spark or fuel related. Any help on this would be greatly appreciated. Thanks guys

How much did you advance it... You're gonna need to always use premium now.

I didn't have a timing light so I'm not sure specifically how much it was advanced. I have a friend that has a time light so I'll be going to his place this week to retard the time back to factory and then troubleshoot from there. Before the timing advance the vehicle did not misfire but had significant powerloss, most noticeable in the 2800RPM and up range.

So far prior to timing advance:

Spark Plugs have been changed
Plug Wires have been changed(eliminated misfiring)
Distributor checks out
Fuel Filter has been changed

[mkernz22]

though i have a 5s, when i first got the car (not realizing the lack of power) i would get on the highway and it would take forever to get up to speed. what i do now is book it down the on ramp lol i usually hit 70 at about the end (90 if im pushing it) of it so it all works out. not sure about NC, but the on and off ramps up in MA are pretty long

This post has been edited by mkernz22: Jan 22, 2011 - 7:11 PM

[j0ch0a94ST]

though i have a 5s, when i first got the car (not realizing the lack of power) i would get on the highway and it would take forever to get up to speed. what i do now is book it down the on ramp lol i usually hit 70 at about the end (90 if im pushing it) of it so it all works out. not sure about NC, but the on and off ramps up in MA are pretty long

Well I've had the car for 6 years and I know how much power it used to have an can tell the noticeable difference. It was painfully slow.

[j0ch0a94ST]

Guess I'm going to run some fuel injector cleaner through it and then check the injectors and grounds