3.4 DOHC Issue.

[chadz34]

Hey guys, I've been away for a while. The Lumina has been very reliable for a long time now. Still runs fine, but there is one problem that bothers me. When I'm WOT, it feels like there is something holding the engine back it sounds fine until 3rd gear, in the higher RPMS 5,000+ the power seems to die off and fade in and out? It does not happen all the time though, whihc is weird. I think it's not as noticeable in 1st and 2nd gear is because it rips through those gears quicker. When I got this car is was pretty mean and still is when it isn't acting like a wh*re.

 

Any input would be appreciated. I was thinking fuel pump, but that would be a constant problem yes?

[Andrew]

you might just try replacing the fuel filter first.

[94 olds vert]

you might just try replacing the fuel filter first.

 

I will x2 that.

[chadz34]

you might just try replacing the fuel filter first.

Ok, I'll try that, I do however change it anually as recommended.

[94 olds vert]

you might just try replacing the fuel filter first.

Ok, I'll try that, I do however change it anually as recommended.

 

Well, then that may not be your problem then...unless its timed to be changed.

[chadz34]

Ok, I'll try it and get back to you guys. It's 12 dollars I think for the filter if I remember correctly.

[Andrew]

every year, wow!

[digitaloutsider]

When did this start happening?

[chadz34]

When did this start happening?

It happens off and on, and has been going on since this past summer. Really audible in 3rd gear you can just hear the engine lose horsepower. The perfect description is fade.....it's not a miss, or a cut out. Just don't understand why it's not consistant.

[RobertISaar]

you might just try replacing the fuel filter first.

Ok, I'll try that, I do however change it anually as recommended.

the one in the monte carlo has only been changed once in the 15 years and 183K miles it hasn't rolled down the road and that was summer of 08. and it didn't need it either, i just thought "what the hell" and did it. does everyone else get shitty gas or what? or have i been lucky?

[chadz34]

you might just try replacing the fuel filter first.

Ok, I'll try that, I do however change it anually as recommended.

the one in the monte carlo has only been changed once in the 15 years and 183K miles it hasn't rolled down the road and that was summer of 08. and it didn't need it either, i just thought "what the hell" and did it. does everyone else get shitty gas or what? or have i been lucky?

I have no clue! Maybe you had the worlds best fuel filter haha.

[RobertISaar]

I have no clue! Maybe you had the worlds best fuel filter haha.

 

factory filter FTW???

 

/hijack

[GOT2B GM]

Put a fuel pressure gauge on it while driving it to replicate the problem.

[chadz34]

Put a fuel pressure gauge on it while driving it to replicate the problem.

How do I read it tho, when I'm driving?

[chadz34]

To UPDATE: after the car loses power it smells of burning cat! Could the cat be clogged, it's the straight tube cat, so it is high-flow stock. I may just cut it out and replace with a piece of straight pipe to complete my loud ass exhaust!

[94 olds vert]

Do it!

 

I cut off my cat and put a straight pipe in.

[chadz34]

How did that work for you? The GM shop told me that with the dual cherrybombs on my car I lack backpressure they actually told me this. I always thought it was a myth....I figure more flow=more go. What did you notice?

[94 olds vert]

I didn't notice more horsepower, but my cat wasn't clogged.

 

I did notice a more aggressive exhaust note. I still have the factory mufflers on my car.

 

I want to put dual cherry bomb mufflers on. I see no problem with back pressure with out a cat and cherry bomb mufflers

on.

[chadz34]

I am going to do this piping that long won't be expensive. Have access to a welder as well! My car is real loud with the dual bombers on it. The cat removal will make this thing whorishly loud. But of my two cars, this one I have no problem modding, painting or workin on. I've raced it, will continue to race it, and it never backs down. I guess the cat job, will complete the exhaust. I did however, want the MilzyMotorsport headers........if they weren't 600 for non coated, and American currency.

[Galaxie500XL]

I've had good success in the past with the so-called "turbo" mufflers some manufacturers make.

 

They've usually got better flow (less backpressure), and the exhaust note is a bit more agressive and deep without getting you unwanted attention from the police.

 

Most V-6 cars I've heard with "cherry bomb" mufflers sound harsh and raspy to my ears....

 

I didn't notice more horsepower, but my cat wasn't clogged.

 

I did notice a more aggressive exhaust note. I still have the factory mufflers on my car.

 

I want to put dual cherry bomb mufflers on. I see no problem with back pressure with out a cat and cherry bomb mufflers

on.

[Skunkworks_Zed]

You do know that you won't pass an etest without a cat, right? Just replace it.

[chadz34]

We don't have etest here.

[Drummer]

My Dads Z34 had the same problem. Tried changing the timing and it got a little better, but still shitty, gutted the cat, still nothing, and this all started after we put new head gaskets on it. Shortly after he sold it.

[chadz34]

The head and intake gaskets were all replaced on my engine roughly 2 or 3 years ago.