00 GA with 3.4L hesitation & misfire [Archive] - GrandAmGT.com Forum

PDA

View Full Version : 00 GA with 3.4L hesitation & misfire


lancerga
04-03-2006, 06:39 AM
I just bought a GA 2000 with 100 miles. It runs awesome starts like a champ, idles like a champ. But when I give it some throttle, it often hesitates like it's running out of fuel. When cruising it's fine but when I give it more gas, often it hesitates. When I want to pass someone it just misfires and accelerates slowly. When in neutral and parked, if I floor it, I hear it misfire and hesitate too.

When it's cold, she's perfect for about 2minutes then starts misfiring at wide open throttle. It's not as bad if I roll on the gas and not floor it. Which may point out to an ignition component problem.

I know my stuff when it comes to that but I want advice from people who know these cars more than myself.

I'm thinking clogged fuel filter or dying fuel pump.
Dying coil pack or bad spark plugs.
Or maybe the fuel pressure regulator won't raise fuel pressure when vacuum drops.

What do you think ?

I have new spark plugs (AC delco platinium) I will install soon. I'll change the fuel filter. What should be next ?

Thanks !! I want my GA to perform like it should !

coupe
04-03-2006, 06:56 AM
It needs a tune up it sounds like.
I would:
New plugs
New wires
New coil packs
New fuel filter
New belt
new PCV valve
CLean egr valve or replace
Coolant flush

nascarnate326
04-03-2006, 07:12 AM
Um, what he said ^

lancerga
04-03-2006, 08:09 AM
It needs a tune up it sounds like.
I would:
New plugs
New wires
New coil packs
New fuel filter
New belt
new PCV valve
CLean egr valve or replace
Coolant flush

Could you narrow it down a bit?

It's like saying change everything and it should fix it. What order should this be done ? Anyways after reading a bunch on the forum about people with similar issues, I have scheduled a Fuel injector cleaning and a fuel filter replacement. If it's not fixed after I will change plugs and wires and then coil packs. We will see what fixes it and I will report.

coupe
04-03-2006, 08:17 AM
I would just do all that in one day with a case of beer and some good tunes man.
I did forget the injector cleaning.
These are things that you ussually would do to a car that has gotten to 100,000, its really just a basic tune up.
New plugs
New wires
New coil packs
New fuel filter
New belt
new PCV valve
CLean egr valve or replace
Coolant flush
Proffesionaly clean injectors

Im not sayin that this will fix it but i bet it might. Almost all those things are cheap and can be done yourself with basic hand tools and the help of the search button on this site.

Mike Jung
04-03-2006, 11:48 AM
Don't forget a new air filter.

When changing the spark plugs, definitely change the spark plug wires too.


Could also be a clogged Catalytic Converter.
(The Cat. & PCM have like a 8-years/130K km Emission warrenty by GM Canada.)


PS: A scan tool or code reader would also be helpful in finding what the computer picks-up.

lancerga
04-03-2006, 01:22 PM
Don't forget a new air filter.

When changing the spark plugs, definitely change the spark plug wires too.


Could also be a clogged Catalytic Converter.
(The Cat. & PCM have like a 8-years/130K km Emission warrenty by GM Canada.)


PS: A scan tool or code reader would also be helpful in finding what the computer picks-up.

Well I know a blocked cat will make you lose power. But my car runs real sweet for the 1st minute. A blocked cat would bog the engine all the time especially at higher rpm/load.

I don't have a scan tool, but I'll have the car hooked up wednesday to check.
I got some wires Bosch premium wires along with AC Delco platinum plugs

coupe
04-03-2006, 01:28 PM
Just go to autozone, they will scan ya for free.

lone_wolf025
04-03-2006, 02:09 PM
Everyone has made some good suggestions so far and you're certainly on the right path yourself. If you feel like spending the money for the tools to do it yourself pick up a vacuum gauge at autozone or something if the injector cleaning, plugs and wires doesn't fix it. The gauge, if you know how to read it, will tell you if there are any mechanical issues in the engine. Basically though if all is good you should see somewhere around 20" of vacuum that if you goose the throttle should drop fast and come back up to the previous number once the plate is closed. Though I'd agree more with your first assesment about the ignition. Everything else like the belt and the coolant flush (the original coolant is technically good for 100k miles) are items that can be checked to see if they're still good.

digitalballz
04-03-2006, 06:53 PM
IT NEEDS A COMPLETE TUNE UP!!! If it has over 100k on it just do it.

lancerga
04-03-2006, 07:33 PM
OK. I put a fuel pressure gauge on it and it read 49 psi at idle and 59 psi @ wot.
The increase in psi seems right to me 20'' vac = 10 psi.

I checked the connectors @ the coil packs. 2 were very rusty. sanded them a bit and cleaned them with electric connector cleaner. One wire was loose and I made it tighter. Didn't change a thing in driveability but at least that's taken care off. I didn't check the spark plug side, maybe they plugs & wires are real old. Going to change them.

So fuel pressure seems fine it looks more and more to be a coil pack wire/spark plug issue.

Also I cleaned the MAF sensor with electric contact cleaner. And it ran slightly rough a bit then came back to it's old self. Good running until you step on it. Sometimes it pulls real nice other time it misfires badly. Maybe the MAF is acting up too.

I think I'll go scrap yard hunting for a low mileage wrecked car with a 3.4 so I'll take all sensors coil packs etc...

digitalballz
04-04-2006, 06:45 PM
Do you listen??? Oh yeah dont clean the maf

gojo83
04-04-2006, 08:27 PM
I hate to sound like a dumbass but where is the egr valve located because I am looking to do a complete tune up also and I need to know where to find it and I also would like to know exactly where the thermostat is also so I can add a 180 degree thermostat when I get all into it. Thanks

Greg

lone_wolf025
04-04-2006, 08:30 PM
Thermostat is easy. Just follow the upper radiator hose to the engine. As for the EGR you'll have to bug someone else or just follow all the wires plugged into things until you find it.

Mike Jung
04-04-2006, 08:36 PM
...I also would like to know exactly where the thermostat is also so I can add a 180 degree thermostat when I get all into it...
P.I.T.A. ! lol

HOW TO: Thermostat Install (http://www.grandamgt.com/forum/showthread.php?t=15821)

iceman
04-04-2006, 08:55 PM
Get the injectors cleaned .. not with that gas additive crap, the real way.

lancerga
04-05-2006, 06:17 AM
Do you listen??? Oh yeah dont clean the maf

Calm down. Breath in the paper bag.


I put in some of our fine Petro canada 94 octane fuel yesterday morning. The car was running better and better with every miles I did. After 10 miles it didn't misfire at all @ wot. It would spin the tires, traction light came on no misfire. I drove 20-30 miles more with no misfiring whatsoever and lots of power.
This morning the came back. It's not as bad as before as I have some 94 octane left in it but I think it's weather related. Yesterday it was very damp.

I'm scheduled to have my injectors cleaned and Filter changed. Next are the spark plugs and wires. Apparently the wires are original because they have numbers on them. Maybe the spark plug are originals too. Hope not because I might have a problem with the threads. So new spark plug wires and spark plugs are coming too.

The tune up will get done.

coupe
04-05-2006, 06:28 AM
You should have done the spark plug wires and plugs first. It is the easiest thing to do.

lancerga
04-05-2006, 06:55 AM
You should have done the spark plug wires and plugs first. It is the easiest thing to do.

Usually lol. I'm a bit worried about the thread coming out with the plugs since they may have not been changed ever.100 000 miles...
Either way I don't really have a choice, they need to be replaced.

digitalballz
04-05-2006, 07:47 PM
it's weather related. Yesterday it was very damp.
:applause: :applause:

That why I said you need a tune up. When it rains and is "very damp' and you get a misfire you need new wires. :banghead :banghead

lancerga
04-05-2006, 08:19 PM
it's weather related. Yesterday it was very damp.
:applause: :applause:

That why I said you need a tune up. When it rains and is "very damp' and you get a misfire you need new wires. :banghead :banghead

It ran better when it was humid outside !

Not the wires, they were fine I use a lot of sprayed water on them and it didn't make a difference

I did the injector flushing (running a injector cleaner pressurized on the fuel rail), put in a new fuel filter. Still had a miss but was slightly better. Took out what I now know as the original spark plugs and the original wires. Wires were still good I believe but the spark plugs were really worn out. The gap was too wide on all of them because of the worn electrode. This is what caused the misfiring I believe. I also replaced the ignition coil that had rusty towers. Total was about 200$

The car now runs like new and has great power. It is fixed.