car still bucking and surging

[Sh3aNz0r]

still having issues with my 1996 grand prix

it bucks and surges after 10-20 mins of driving, but its not every time that it does it.

i replaced the battery, alternator, starter, plugs, wires, coil packs, and still this thing refuses to run correctly. i even went as far as to disconnect the front o2 sensor thinking it could be bad sensor that wasnt relaying correctly, and even in open loop, the car still continues to run like crap. i have noticed that the car still appears to be getting parasitic loss. if i sit at a traffic light, the turn singal blinks very slow, and as soon as u rev the engine up or start accelerating away from the light, it starts blinking like normal. im really at a loss now. no check engine light, and the battery light starts to illuminate as its about to die, then goes out as it surges back up, and back and forth. also the ABS light comes on usually just before or a few seconds/mins before it starts acting up.

i am aware the ABS light usually comes on when there is an electrical issue to shut the ABS off to reserve power, but other then replacing the battery cables i don't know what else to try at this point.

any suggestions, please let me know

Brandon

[bszopi]

Have you checked all of the ground wires and connections?

[Sh3aNz0r]

Have you checked all of the ground wires and connections?

no i was thinking about heading there next and possibly replacing the negative and positive battery cables as well

[Sh3aNz0r]

still having bucking and sputtering issues. recently replaced the evap purge solly because i was getting a check engine light for that, and the light came back 3 hours after replacing the sensor. also the oil level sensor was shot so i replaced that when i did my oil change the other day.

here is the thing. i have noticed that the car usually only acts up durring expressway or med-heavy acceleration on left had turns or bends, or sometimes when you go over a bump that causes the whole car to move. (Bridges, and uneaven pavement section switches). im really looking fo any ideas out there because at this point i have no more ideas since the fuel pressure is good even when the car acts up, i had a tech 2 on the car for over a week while driving and it gave nothing for an idea.

I have replaced so far: Plugs, wires, 3 coil packs, ignition controll mod, ECU, battery, alternator, starter, positive and negative battery cables, fuel filter, oil level sensor, evap purge solly.

i have also disconnected the EGR, MAF sensor, and front o2 sensors and driven the car with them disconnected one at a time and it still acts up.

Not sure if its possiable but could it be the cat converter clogging up? I am now getting a P0420 error but i dont know if i killed the cat from all the extra fuel thats been dumping into the exhaust when the car is acting up.

also if anyone can tell me what the o2 sensor readings should be under normal correct function that would be great, i know the values are waveryign back and forth, but i dont know what they should be at.

PLEASE HELP!!!

Brandon S.
1996 Pontiac Grand Prix 3.1L OHV M Motor

[merlot566jka]

eh, i hate your kind of problem!

sounds like something is loose or something is exposed and grounding out.

i would first assume it has to do with the alt. (have you tested to verify the new alt is working properly? ive seen many 'new' parts fail days after they were installed) try to put the car on a batt charger at 40amp and see if the problem still happens. if so, i blame the alt. to further test it with the charger, put your foot on the brake (ebrake on too) and put it in gear. if it doesnt bog with the charger, remove the charger and try again. if it bogs, then you know its a power issue.


next id check the grounds and batt cables. make sure that starter hot wire is bolted on all the way. it may be a pain in the ass, but a continuity test on the batt cables would eliminate them as a problem. also, make sure you have a good connection to the battery, corrosion and worn terminals cause some annoying problems.

and yes the cat could be clogged. have it checked out. or put it on a lift, give it a good knocking from the fat of your palm, if it rattles....bingo! or have it pulled off and see if substrate comes out, or if its not see thru.
but it would be hard to say this is the problem...yet i have seen crazier things happen.

[jonbourg]

no i was thinking about heading there next and possibly replacing the negative and positive battery cables as well

I'd check connectors/grounds before doing anything else. Also was there any recent maintenance done before this happened? Where was the monkey last. That's where I would look first. This sounds like something electrical, but I doubt it's a major component. It really seems to me it's a loose ground or other connection. If that's not the case look for shorts. Also look for corroded connections. Corrosion can either cause a change in resistance and a corresponding voltage drop or a current drop.

My other suggestion would be to look at the fuel delivery system.

[Sh3aNz0r]

so as i was getting ready to cut the cat out of the car to ram the packing out since i am receiving a Check engine light for the cat now, i found 2 wires that appeared to be in direct contact with the exhaust manifold on the firewall side of the block, i disconnected the cable, which i noticed was going to the crank sensor and to the ignition control module, moved it enough that it was no longer touching the manifold, and the car ran great for about 6 days. Yesterday as i left for a 40 min trip to an amusement park, i didn't even get off my street and mayhem ensued with the car going back to the same old bucking and sputtering. Now mind you i replaced the alternator because the car was doing this bucking and surging thing and even after replacing it the car does the same thing, so i would tend to doubt it is that. also i replaced the positive and negative battery cables, and the battery, and the starter so all those wires and connections are corrosion free. now when the car acted up yesterday, i got out and moved the crank sensor wires all over and even pushed them against the manifold to see if it was what was causing the bucking if there was a bear wire or something of the sort, and the car did nothing, it acted fine. put it in gear, roasted tire back down my street and as i went to back into my parking spot, the bitch shut off on me. so i looked at my girlfriend in confusion and said ok WTF. restarted the car, put in reverse, started moving and surprise surprise it shut off again. now i have checked fuel pressure even while the car was acting up and no changes to pressure at all, so i cant blame the fuel pump. anything else to try before i have to replace this POS cat converter?

[turboD]

Take a good close look at the crank sensor and the crank sensor harness. The crank sensors will wick oil into the connector and into the wires - breaks down the insulation on the wires and causes them to ground to the internal shield covering or to themselves. Be very carefull when pulling the crank sensor out as they also get stuck in the block and have cracks in the main sensor body due to heat and vibration.

[IanSzgatti]

On the bright side you have a shit-load of new autoparts.

[IanSzgatti]

For real though I'm leaning toward either a bad voltage regulator on your new alt, (freak chance), or an ECM problem caused by feedback from your old alt.
Have the new alt checked for ripple... double check bat load, etc...

You might want to check some values in the computer though, make sure it didnt puke on you.

If the electrical trouble is isolated, fixed, and car still bucks look at the fuel pump... could be acting up once it's warm