electrical or fuel problem?!?! [Archive] - GrandAmGT.com Forum

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1badgagt
03-03-2013, 08:12 PM
please check this video out. kinda hard to explain.

http://www.youtube.com/watch?v=3B3WtLQvGFs&feature=youtu.be

At first it started just losing power when you mashed on the gas pedal. drive it like a white man and its just fine. now just recently it started bucking, back firing, and the rpms are bouncing crazy as seen in the video. this is happening just driving normal and not flooring it. sitting at an idle it is fine. purs like a kitten. but give it gas and it sounds like a tiger with pneumonia.

I have changed intake gaskets and head gaskets (last year), spark plugs, wires, fuel filter, oil and filter, and today I changed fuel pressure regulator. im about stumped as to what it could be. there are no service lights illuminated either. any input as to what you guys think could be the culprit or any questions please help me out. its been running great the past few years until now. HELP!!!

Jimmayy12
03-03-2013, 08:41 PM
I've never seen anything like that before. Thats pretty strange. Can you drive it fine?

1badgagt
03-03-2013, 08:44 PM
its drivable I guess, stalled on my way home earlier and wouldn't start right away. fuel pump is definitely priming (can hear it). but whats weird is this only happens when you tough the gas pedal. idles absolutely normal.

Jimmayy12
03-03-2013, 08:46 PM
Thats really strange. Are all the wires connected on the pump properly? Really strange.

1badgagt
03-03-2013, 08:53 PM
yeah. they've never been touched..never needed to be. it started a month ago. would just hesitate and lose power on highway if you floored it. and now this no matter how fast your going

bricooper78
03-03-2013, 08:53 PM
1, clean your Mass Air Flow sensor.

It's the big aluminum square in the air tube that goes from the filter into the intake. There is MAF cleaner available at any parts store, don't break the little strands in there!!!! If there are pieces of carbon in the mesh part, you can take a toothpick to them and knock them out, but BE CAREFUL OF THE WIRES!! If one is broke, that's your problem.

But start with that, if that's not it, then you can go on into other areas, but lets check that first.


If that changes nothing, pull the spark plugs, the front side, from the passenger side are labeled 1,3,5. backside is 2,4,6. Post a pic of each one if you'd like, see if it's wet with gas, that would indicate a coil pack or bad wire... The ignition control module could be effing up and not advancing spark or something, but the MAF is a great place to start with that problem

1badgagt
03-03-2013, 08:56 PM
doing that tomorrow. I had it off changing the FPR today and didn't think to look there. plugs were a tad bit white last checked (month ago when it started). ill update tomorrow to see if it helps of fixes the issue

bricooper78
03-03-2013, 09:03 PM
Okay, well my tracking would be MAF, Plugs, (double check gap on them too), wires, and then back to the coil packs. O'Reilly can test them, he says here "If they test bad, they're bad, but sometimes they test okay, but they're not" lol

kzulfic
03-03-2013, 09:04 PM
Are you running the original catalytic converter? I'm asking because of the progressive down grade in performance and that you mentiond the head gasket and if that had gone out could have caused the cat to clog sooner, but if you are still running the original cat, I could just be old and worn out too.

bricooper78
03-03-2013, 09:07 PM
^I was going to tell you about the cat plugging, but figured we'd hope for better news

1badgagt
03-03-2013, 09:15 PM
wouldn't the maf turn the cel or svs light on though??

kzulfic
03-03-2013, 09:18 PM
^I was going to tell you about the cat plugging, but figured we'd hope for better news

I hope in his case it is.....

1badgagt
03-03-2013, 09:18 PM
Are you running the original catalytic converter? I'm asking because of the progressive down grade in performance and that you mentiond the head gasket and if that had gone out could have caused the cat to clog sooner, but if you are still running the original cat, I could just be old and worn out too.

original cat is still on the car. the performance was intermittent the last month. all before today it was fine until the occasional lack of power. (rpms rise but no power) at WOT.

1badgagt
03-03-2013, 09:33 PM
btw incase it wasn't obvious, that's full throttle in the video. notice in 7 seconds I only gained like 1 mph.
going to check maf, plugs again, I know the coils aren't corroded, just changed wires (figured it would help). someone told me the egr could cause this but I I never heard of an egr causing this

bricooper78
03-03-2013, 09:36 PM
EGR is exhaust, that screwing up would probably trigger a CEL light.

(It generally lights up when there is something emissions related)

1badgagt
03-03-2013, 09:39 PM
yeah I know, just doesn't make sense why nothing is throwing a code. maf should, it did a couple years ago but wasn't acting crazy or nothing. no miss fires nothing. it did backfire a couple times though????hmmm

bricooper78
03-03-2013, 10:12 PM
It's odd when they don't throw codes for stuff that it seems like they should be all over, that's for sure. That hopping looks like the advance my old S10 had an issue, and I changed the cap and rotor to fix it, which now the coils/packs take place of, so it's entirely possible.. But, there are a couple things, so it's best to start with a cheap thing, looking at a sensor, and when you go to get cleaner, take the packs and have them tested, might find the problem right there!! I'll cross my fingers for ya man, it can be a headache!

1badgagt
03-04-2013, 06:00 AM
i honestly think the cat is plugged. performance has been degrading over the last month. that is one thing that will not normally throw a code. my 94 trans am did the exact same thing last year. minus the stalling. cut the cat off and it ran like a champ. going to clean maf and gut the cat today (just to see if problem stops)

DaRkWaVe
03-04-2013, 09:10 AM
Just thought I would suggest the Throttle Position Sensor. Vacuum leak is also possible. Good Luck man. I would crap my pants if my car started doing that...

1badgagt
03-04-2013, 12:08 PM
checked all the vacume lines...nothing there. and it idles perfectly fine. im staying away from tps only because i havent had any throttle sticking issues. iac valve would be my bigger concern but thats functioning fine. im goin cave man on this when i get home from work. sledge and pipe. no more honeycomb for my cat hahahaha

1badgagt
03-08-2013, 07:14 PM
end result was a bad crankshaft position sensor. put a new one on and VrOOOOm.

DaRkWaVe
03-09-2013, 04:03 AM
Thank you for letting us know what the problem was.