2001 Buick Century 3.1 66k miles, Very sluggish

[bigboi407]

ill explain this is simple and Easily as possible.........

Say you get in the car, turn it on, put it in Drive, you punch it to the floor, the car picks up speed as normal, BUT Feels as if the whole transaxle is shaking, and it feels as if it is coming from the whole front side of the transaxle/engine assembly is shaking forwards and backwards as the car is accelerating but it ONLY Does it when you punch it, Imagine if a Control Arm/Tie Rod end broke off and the Wheel closest to the front of the engine Can Sway forwards and backwards, thats as best as i can describe this

and i will admit... Yes we do hit the gas quite a bit to avoid the idiots on the road, i seem to have a (Crash-into-me) magnet...


But now the car is starting to consume more gas than normal..... i took it to AZ the guy printed me 4 codes here are as follows....

P0301 - Cylinder 1 misfire (has always been there idk whats causing it, no idea)

P0404 - EGR Code

P0446 - EVAP Purge/Vent solenoid circuit condition (WTF is this?? O.o)

P0452 - Fuel Tank Pressure Sensor


i did buy an aftermarket pump from a reputable guy on ebay, and I myself installed it, but theres a problem with it that i think I caused, the gas needle will go up to full at random and stay there then go all the way back down to where the level actually is.

All the help is appreciated...


My 86 Civic is in the process of being painted and as soon as its done i myself am never driving this buick again (not to diss GM, i want a GTP, but F this Century in the rear)

[pocket-rocket]

P0301 - Cylinder 1 misfire (has always been there idk whats causing it, no idea)

P0404 - EGR Code

P0446 - EVAP Purge/Vent solenoid circuit condition (WTF is this?? O.o)

P0452 - Fuel Tank Pressure Sensor

P301 could be either a plug, wire or internally shorted coil pack.

P404 could be a plugged EGR passage or stuck EGR valve itself.

P446 I would assume could be a broken wire, grounded wire or unplugged solenoid. This is only speculation on my part.

P452 could just be the gas cap, but considering you've just had the tank down it could be a disconnected sensor or it might have gotten jarred loose since I don't think GM bolts those down and would kinda pop into place. This on is speculation on my part as well.

Hope this helps man, car frustrations suck. I just got done being frustrated at the wife's car. I was so irritated I was about to put my fist through the window. The only thing that kept me from doing it was then I would have to fix it, and how many Daewoos (Daewii? Lol) do you see running around?

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[TGP37]

Does your tachometer bounce around when it acts up? If yes, good chance it's a bad electrical connection of either power supply or main ground to batt -.

Your EGR may be stuck open. If it was a coil, I would think both cyl 1 & 4 will misfire. Of all those codes, they may not be the cause of the shuttering in WOT. Except cyl 1 misfire. I have had my EVAP system unplugged and still ran fine.

Cyl1 misfire, could be bad injector, bad injector seal at the LIM, bad spark plug, bad plug wire, improperly connected spark cable, bad seal (burnt valves, rings, gasket blown, cracked piston)....



I would start at the EGR and inspect the plunger for carbon build up. You can use two quarters placed between the EGR and the LIM port to seal it off temporarily as a test, a small sheet of metal cut to size will work too. I removed my EGR.

Check your engine mounts up top in front. Make sure they are nice and tight.

You should also jack up the front end and check for excessive play in the front wheels. A google search will provide what axis of play is related to what component.


The way I see it, it could be a bad ball joint, tie rod end or other mechanical failure. OR it could be severe misfiring causing the bucking.

[bigboi407]

Does your tachometer bounce around when it acts up? If yes, good chance it's a bad electrical connection of either power supply or main ground to batt -.

Your EGR may be stuck open. If it was a coil, I would think both cyl 1 & 4 will misfire. Of all those codes, they may not be the cause of the shuttering in WOT. Except cyl 1 misfire. I have had my EVAP system unplugged and still ran fine.

Cyl1 misfire, could be bad injector, bad injector seal at the LIM, bad spark plug, bad plug wire, improperly connected spark cable, bad seal (burnt valves, rings, gasket blown, cracked piston)....



I would start at the EGR and inspect the plunger for carbon build up. You can use two quarters placed between the EGR and the LIM port to seal it off temporarily as a test, a small sheet of metal cut to size will work too. I removed my EGR.

Check your engine mounts up top in front. Make sure they are nice and tight.

You should also jack up the front end and check for excessive play in the front wheels. A google search will provide what axis of play is related to what component.


The way I see it, it could be a bad ball joint, tie rod end or other mechanical failure. OR it could be severe misfiring causing the bucking.

i do know that mount on the very front of the motor is blown, there is grease everywhere and its GROSSS......

doesnt have a tach...

ill try moving the coil pack see if the misfire follows (a mechanic i spoke to said only 1 side CAN go bad, not often but it can happen he says)

it was suggested i do the whole intake manifold gasket set in steel, and clean the EGR port, and clean everything as best as possible.

i will get the injectors cleaned.

my friends moms boyfriend has a car lift and a full work shop, full of tools, im thinking of asking him to lemme use the place, jack up the car check for play, take the wheels off, and check for play with anything....

the guy i spoke to was not a mechanic that works for a shop he has a shop at home and works for someone, so hes not pitching me bullshit lies..

as for the fuel tank pressure sensor, idk wtf.....

i know for a fact bro that the shaking is not a misfire, when it shakes the Whole dash/floor/seats shake and the engine is revving like a symphony...

This Gents...... is one clogged EGR port, EGR was left wide open in my dads ford aspire

[TGP37]

"i know for a fact bro that the shaking is not a misfire,"....... yet you can't find the problem. Not saying your wrong but persistent assumptions can cost a lot.

Mount is blown with grease all over.....that can make the engine rock around pretty good and will ruin any other mount in short order.

I seriously doubt the coil failed on one side and not the other. They are sensitive to damage, cracks, etc. They are nothing much more then 40:1~60:1 transformers. You can pull the cable and place a plug in it and have a friend turn it over. You'll know if it sparks or not. Or just swap places with another coil and see if the misfire follows.

Fuel pump pressure sensor could be something as simple as a bad ground, cut wire, burnt wire (high resistance)

Your mechanic friend doesn't have to lie to be wrong.....shit happens.

That EGR looks like an impending heart attack, lol



I think what is happening is this.........when you punch it the torque rocks the motor back against the broken mount. At that point something may be grounding or a wire is failing and causes the normal operation to fail. As soon as the motor lunges forward (from a quick failure) the engine runs normal again. The process repeats creating a heavy rocking.

My car had a bad wire once and all it took was a slight wiggle of the harness and the engine shut down. Even closing the hood hard would shut it down sometimes. Under load the wire failed, the engines very slight motion caused an on/off scenario making the car jerk and buck around heavily.

That is just a logical guess, something to consider but may not be the real issue.

[bob442]

Get a scanner and see if a clutch pack is slipping. You will have to monitor tcc input and output speeds


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[bigboi407]

"i know for a fact bro that the shaking is not a misfire,"....... yet you can't find the problem. Not saying your wrong but persistent assumptions can cost a lot.

Mount is blown with grease all over.....that can make the engine rock around pretty good and will ruin any other mount in short order.

I seriously doubt the coil failed on one side and not the other. They are sensitive to damage, cracks, etc. They are nothing much more then 40:1~60:1 transformers. You can pull the cable and place a plug in it and have a friend turn it over. You'll know if it sparks or not. Or just swap places with another coil and see if the misfire follows.

Fuel pump pressure sensor could be something as simple as a bad ground, cut wire, burnt wire (high resistance)

Your mechanic friend doesn't have to lie to be wrong.....shit happens.

That EGR looks like an impending heart attack, lol



I think what is happening is this.........when you punch it the torque rocks the motor back against the broken mount. At that point something may be grounding or a wire is failing and causes the normal operation to fail. As soon as the motor lunges forward (from a quick failure) the engine runs normal again. The process repeats creating a heavy rocking.

My car had a bad wire once and all it took was a slight wiggle of the harness and the engine shut down. Even closing the hood hard would shut it down sometimes. Under load the wire failed, the engines very slight motion caused an on/off scenario making the car jerk and buck around heavily.

That is just a logical guess, something to consider but may not be the real issue.

i would bet my left nut on Cyl 1 misfire not having anything to do with the rocking........ its not a rocking motion its more as if the right tire Upper and lower control arms are all moving forwards and backwards, The engine Sounds like symphony, u can hear her PURRR when u punch it to the floor, the rocking is coming from something else, and i dont believe it had anything to do with any clutch packs, BUT Given the true fact that the engines Front mount is out it, making the others go bad, causing play with the complete transaxle on the P/S wheel assembly??


I am CERTAIN its not a clutch pack or Cyl 1 misfire causing the shaking, I know ive screwed up on some things, but we can eliminate those possibilities guys, i know i sounded like a dum-b-ass when i didnt know that a clogged cat could cause a car so many problems....

i think theres something goin on with the shaft/knuckle/tie-rod/LCA area ON TOP of the front mount being out.....

As for Cyl 1, i am betting a clogged injector because the car did have a clogged fuel filter and dirty ass fuel pump, And while on that subject Could the Screen on the Fuel Pressure regulator clog up and cause issues?

as pertaining to this car having 75k and never having any intake manifold work done do it, should i rip out the fuel rail/injectors, get the injectors cleaned, new fuel pressure regulator, clean the intake and EGR system, and a new solid front mount??

[TGP37]

Fuel system should be fine if only cyl1 is misfiring, except for the injector. Could be something else though.

Jack up the front tire, either 1 or both.

push/pull at top and bottom of wheel. If you get play it is the ball joint or the bearings.

Push/pull at the sides (9-3 oclock) if you get play there then it is the tie rod.

You might have a very minor amount of play and that not be the problem. But no play is the proper condition.

Could also be a lumpy tire. I have found a lumpy tire making wobbling only after decel and cruising. Apparently during acceleration the torque smoothed the tire out.

[pocket-rocket]

Have you tried to replicate it by jacking it up and ruining it in gear with the brakes partially applied so you can watch what's moving.

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