running wierd... :-(

[GTfiend]

Ok so heres the deal... bought the car a year ago ( 2002 GA GT 3.4 with 119k MI) ran fine till about 2 months ago. before that i was getting around 23mpg now im getting about 14mpg. when im in drive idling at a stop sign i can feel kinda like the engine is struggling and its vibrating. like a constant reoccurring droning type of feeling. actually it happens no matter what gear its in but its more noticeable in drive.

What I have replaced/fixed:
Plugs
wires
fuel filter
fuel pressure regulator that was leaking
Intake air temp sensor connector
air filter

I also paid to get the injectors cleaned professionally a while back. I have no check engine light on. BUT it seems like the car is getting harder to start. I will turn the key and it will have to turn more and more to get it running. I was thinking ignition coil pack? any input is appreciated! ( I did search... nothing really answered my question)

[bricooper78]

Is there any way you can get a vid of this and put up here?

[GTfiend]

Originally Posted by bricooper78

Is there any way you can get a vid of this and put up here?

i will see if i can borrow a camera. i dont know to much about cars but I did do all the above stuff by myself... but im guessing my engine is misfiring... i dunno. just irritating cause if I wanted 14mpg I would have bought a truck!

[bricooper78]

B'ah, my truck is about 12mpg you're still doing better...

You have no sort of engine light, and it's running bad. Vacuum line leak comes to mind, first thing, check to make sure they're plugged in all the way, the pcv valve, it's on top of the valve cover, has a bend on top of it, then hose, then another bend back around on the top of the motor, that being up top, it could've got knocked loose, and it may not be "off" but it isn't tight either, something like that could make you have some issues.

[GTfiend]

Originally Posted by bricooper78

B'ah, my truck is about 12mpg you're still doing better...

You have no sort of engine light, and it's running bad. Vacuum line leak comes to mind, first thing, check to make sure they're plugged in all the way, the pcv valve, it's on top of the valve cover, has a bend on top of it, then hose, then another bend back around on the top of the motor, that being up top, it could've got knocked loose, and it may not be "off" but it isn't tight either, something like that could make you have some issues.

hahaha.... forgot to mention today I had it in and they checked vacuum with a gauge and said it was fine. they couldnt figure it out. The guy said 14mpg is good... i call BS.

[bricooper78]

Well, with winter blend, in town, "hot rodding" it (i'm old, so i usually kinda just cruise, take that into mind ) i get about 17. that's with a Cold Air Intake (the CAI you read about) and I was messing with some ducting from the driving light hole back to the filter when I got that reading.. never really checked after. Stock air intake, 75 degree day, on the highway, one time I got 36mpg, but that was the only time i got that much, I assume I had a good tail wind.

14 is a bit low, but you're further north than me, and I know our winter blend kills the mileage, especially if you're on 89octane. use 87 (no ethanol, all gas, higher $ but gives you more mileage by 1 or 2 mpgs) and see if that helps any. it will still be a winter 87, but may help you out to get you up to 17ish

[Starglow]

Originally Posted by GTfiend

What I have replaced/fixed:
Plugs
wires
fuel filter
fuel pressure regulator that was leaking
Intake air temp sensor connector
air filter

Check your coil packs for corrosion on the spark plug wire terminals or just replace them. Also clean the MAF sensor because it gets dirty over time which can affect air/fuel mixture ratio and in turn gas mileage.

[GTfiend]

Originally Posted by Starglow

Check your coil packs for corrosion on the spark plug wire terminals or just replace them. Also clean the MAF sensor because it gets dirty over time which can affect air/fuel mixture ratio and in turn gas mileage.

is that the only thing that will make them bad is corrosion? how would I test them?

[MAC the KNIFE]

just pull the rubber boot off of the pack's metal plugs. at 100k miles, 5 of mine were fine, but there was 1 that was rusted awfully. i removed the rust and covered each plug with di-electric grease before plugging the rubber boot back on.

[GTfiend]

if one was not working properly wouldnt it trip ses? better yet wouldnt a misfire trip SES?

im gonna test them with a multimeter later. at this point im hoping one is going out cause im sick of trying to chase this problem down

[jonny]

they checked vacuum with a gauge and said it was fine. they couldnt figure it out.
did they hook it up to a scanner, just because there is no light on now. there could be a code stored in the computer. auto zone or other parts stores will scan it for free.

[GTfiend]

Originally Posted by jonny

they checked vacuum with a gauge and said it was fine. they couldnt figure it out.
did they hook it up to a scanner, just because there is no light on now. there could be a code stored in the computer. auto zone or other parts stores will scan it for free.

Had it scanned at autozone last night... No codes. :-( I did take off all 3 coil packs and check them for resistance. from left to right i got 5.96k 5.93k 6.03k ohms...

[GTfiend]

Maybe its not even a misfire. what else can cause the engine to shake or pulse a little while at idle at a red light in drive? You cant tell on the tach but to me it just feels uneven... Im making a drive to north Carolina in april so I gotta have this thing running ok.

[bricooper78]

Idk if the EGR (exhaust gas recirculation) valve may be going on you, but that would trigger the light and a code... or it should anyway.

did you clean that MAF sensor? they do carbon up, can of cleaner is 6 bucks... also, the actual throttle body gets carbon too, that may not be a bad thing to look at, just make sure the intake side is clean, since you've cleaned the fuel side.

[jonny]

Originally Posted by GTfiend

Ok so heres the deal... bought the car a year ago ( 2002 GA GT 3.4 with 119k MI) ran fine till about 2 months ago. before that i was getting around 23mpg now im getting about 14mpg. when im in drive idling at a stop sign i can feel kinda like the engine is struggling and its vibrating. like a constant reoccurring droning type of feeling. actually it happens no matter what gear its in but its more noticeable in drive.

What I have replaced/fixed:
Plugs
wires
fuel filter
fuel pressure regulator that was leaking
Intake air temp sensor connector
air filter

I also paid to get the injectors cleaned professionally a while back. I have no check engine light on. BUT it seems like the car is getting harder to start. I will turn the key and it will have to turn more and more to get it running. I was thinking ignition coil pack? any input is appreciated! ( I did search... nothing really answered my question)

i would try the ignition control module, i think it is weak spark that's why it runs rough at ide.

[GTfiend]

Cleaned MAF already. Checked ignition coil packs. If the coil packs are good wouldn't the icm be ok?

[GTfiend]

Well icm tested good at auto zone... testing fuel pressure at the fuel rail. If thats not it I'm pouring gas on the car and lighting a match

[GTfiend]

Well fuel pressure tested at 48 psi so I'm pouring gas all over the car as we speak... gonna go find some matches. I'm never buying GM again.

[greddy2race]

post a video of that...

[unchained_01]

Check the 02 sensors and the egr for blockage And also did you replace the o rings on the injectors ?