2001 Buick Century 3.1 66k miles, Very sluggish

[bigboi407]

hi all, my first post on these forums, most certainly wont be my last, so my Gf's 2001 buick century that has 66k miles Recently became Very sluggish and wouldnt really drive good AT ALL, she got this car from her mother with 55k miles, ran okay when she got it and just got worse and worse....

this week i have changed the fuel filter, I Seafoamed the engine, Smoked out the neighborhood then changed the oil.. It has stopped coughing when i punch the gas, But say i punch it at the top of 2nd, it WILL NOT change into 3rd until i let off the gas and it makes a knocking sound, Due to Valve Float?? and it also makes a sound like if the TQ is going out, when going uphill it has Torque Shudder, and around 60mph when it downshifts it has a light torque shudder sound but not any shake, i havent dealt with A/Ts for some time.

When taking off, if i slowly press the gas it will bog down and wont move until i reset the accelerator position, sometimes it will work through this bog and GRIP n RIP and Goo.

IT is not throwing ANY Check Engine light or nothing, just runs hella sluggish but doesnt cough like before the new fuel filter, id like to able to fix this problem ASAP and i HOPE i dont have to cchange the TQ,

In a 1991 Lesabre i had, i had the same bog issue, turned out to be the Ignition Module, this may be a different problem same symptoms tho

[60dgrzbelow0]

Welcome to the Forum, "BigBoi"

Have you either changed or cleaned any of the air flow related sensors or checked their connections? If the MAF Sensor is clogged and dirty, it won't alert the PCM of how much air is available on demand and the engine will run lean and bog down as one result. Have a look at this worthwhile read just to get your feet wet on the subject:

http://troubleshootmyvehicle.com/gm_maf_clean_3.8L/cleaning_gm_maf_1.php

As for your TC (TQ?) Torque Converter... pulling the access panel at the bottom of bell housing/AT and rotating the contact fastener locations might reveal loose bolts not holding it solid to the engine flexplate...and on occasion, even reveal a cracked flexplate as well.

[bigboi407]

yes i meant TC.... i thought about that 10 mins after i logged off and said to myself.... TQ???? WTH was i thinkin?? ehh the guys will know what im talkin about...

no i havent checked much of anything besides what i already described in my first post, as im not too fond of newer engines/cars, Another person i spoke with said the same thing... i have changed the spark plugs And the Wires, Now when i hit the gas it will jerk and jump when the bogging occurs, and Now i notice a Vacuum leak sound (Sounds as if coming from the D/S of the engine bay, but then the sound goes away once the engine works through the bog, which confuses me...

Just to confirm, i can use Brake Cleaner to clean the MAF, correct?? MAF Cleaner ive been told by most is just Glorified brake parts cleaner

Something Worth mentioning, The old original plugs i pulled Were more white than the usual Brown/coffee color like most plugs infact indicating a lean condition, correct?

I am not TOO familiar with newer vehicles, this 2001 is the newest thing ive had to deal with, but i know the basic rules of mechanic work so i can take apart anything pretty much, theres just alot more electrical components than i am used to

Thanks i will look through it a lil later

[95SleeperAcheiva]

Sounds like she going lean on you. Check your fuel pressure. I've seen dieiing fuel pumps give just enough pressure to run and no power. Also, if you find the pressure is low, check the harness for a short. They like to develop intermittent shorts at the plug to the fuel sender. That means supply 12 volts to the pump and wiggle the harness looking for voltage drop.

If you can put a scanner on it with datastream you can watch the O2 sensors and see if they are reading lean even though the ecu is demanding rich mixture.

[60dgrzbelow0]

.. and Now i notice a Vacuum leak sound (Sounds as if coming from the D/S of the engine bay, but then the sound goes away once the engine works through the bog, which confuses me...

Just to confirm, i can use Brake Cleaner to clean the MAF, correct?? MAF Cleaner ive been told by most is just Glorified brake parts cleaner

Something Worth mentioning, The old original plugs i pulled Were more white than the usual Brown/coffee color like most plugs infact indicating a lean condition, correct?

I am not TOO familiar with newer vehicles, this 2001 is the newest thing ive had to deal with, but i know the basic rules of mechanic work so i can take apart anything pretty much, theres just alot more electrical components than i am used to

Thanks i will look through it a lil later

I would NOT recommend using Brake Cleaner ...unless you insist on buying a new one when that one gets ruined by the cleaning. The CRC MAF Sensor Cleaner costs damn near the same thing and is designed not to damage the sensitive parts inside the sensor. I concur with both of you that the spark plugs indicate a very lean cylinder burning condition. When you can read those plugs as having a "Nice, Golden, Fried Chicken Brown" colour...you'll be in the ball park. As for the potential vacuum hose leak... these are easy to diagnose with some persistent detective "feel" work around all the connections as a bad hose may not easily reveal itself without some mild bending and tugging adjacent the connection points. An open vacuum as well can affect engine power and if it subsides after the engine warms up, it might indicate the connection point to the hose has heat expanded big enough to temporarily seal the errant hose.

[bigboi407]

I would NOT recommend using Brake Cleaner ...unless you insist on buying a new one when that one gets ruined by the cleaning. The CRC MAF Sensor Cleaner costs damn near the same thing and is designed not to damage the sensitive parts inside the sensor. I concur with both of you that the spark plugs indicate a very lean cylinder burning condition. When you can read those plugs as having a "Nice, Golden, Fried Chicken Brown" colour...you'll be in the ball park. As for the potential vacuum hose leak... these are easy to diagnose with some persistent detective "feel" work around all the connections as a bad hose may not easily reveal itself without some mild bending and tugging adjacent the connection points. An open vacuum as well can affect engine power and if it subsides after the engine warms up, it might indicate the connection point to the hose has heat expanded big enough to temporarily seal the errant hose.

i did notice that it only does it ALOT when first started, but once its warm it doesnt do it anymore.

it drove great on the interstate as far as how the engine ran, i have to be Very sensetive with the accelerator above 60mph as tapping it a hair too far will make it downshift and the car wont go anywhere, i can pickup speed faster by not letting it kick down

okay i know the red can of spray that ur talkin about, ill try that out tomorrow.

It still eats alot of gas, id estimate we will get 55 miles or so per every 1/4 tank, i know its done a diff way but to me that seems like a low MPG

VITAL UPDATE!!: The car has started to throw a code and she said it has started bogging/putting and almost wanting to cut off... which if i remember correctly will come out to be the MAF, i myself have not driven the car so i do not know the exact symptoms since, thats what she described to me whn she took it to the store

[Merc6]

The breather tube that starts in front of the TB next to the air temp sensor and runs to the back cover leaks on cold start but seals up again when it was warm. The rubber grommet on that piece went bad for mine. No auto store caries it or could find it so I went digging in the Pull-A-Part for one that was in good shape. 3100(non LG and 3400 had a slightly different bend cause of the newer air box and zip tube. I ended up getting both for the top swap later on. Will take a pic side by side one of these days.

[bigboi407]

i cleaned the MAF sensor with the spry and there was no change, still does the same bogging..


the CEL was a misfire code, i did not install the plugs incorrectly or forget to plug one in NOR does it sound like it... So im guessing Coil packs are next.... gotta love AZ's Return policy, if thats not the problem i can easily return the new coil packs, if not ill do the same with the module... itsn ot throwing ANY Codes which leaves me scratching my head.

As for the shifting, it likes to kickdown insanely low and top out engine RMPs and even if i get it to downshift into the prev gear, it will not go any faster than if i were to cruz in the gear i was in before, Is this normal??? id like more input on that if possible...

[SappySE107]

I am wondering how good your cat is. As they get clogged up, they perform worse and worse. Really could be any number of things, like the O2 sensor or injectors not spraying in a good pattern. Scanning the computer would help a bit, to see if the O2 is operating properly. If you put a location, someone may be close enough to you with a scan tool to help.

[bigboi407]

I am wondering how good your cat is. As they get clogged up, they perform worse and worse. Really could be any number of things, like the O2 sensor or injectors not spraying in a good pattern. Scanning the computer would help a bit, to see if the O2 is operating properly. If you put a location, someone may be close enough to you with a scan tool to help.

Im in Orlando FL Area, what scan tool are you talking about because the cheap units AZ have dont bring up anything besides the code it had yesterday which went away.

theres no chance of it being the coils or module?

[SappySE107]

I use HPTuners, but that also lets me tune a car as well as scan. Coils usually cause misfires and get worse as the car warms up. Module usually just dies. I wouldn't say it is impossible for it to be those, but it wouldn't be on top of my list. You can check the coil packs for resistance to see if they are bad that way.

That is a bit of a drive from where we are located, but if you find yourself down this way let me know.

[bigboi407]

i still wonder about how it performs on the highway, transmission is very sensetive, likes to kickdown to like 2nd ALL the time... sometimes i can get it into 3rd and it will go Slowly but surely, But most of the time its Either ride out 4th gear which yields a better pickup speed than 3rd OR it kicks down to 2nd and the motor maxes out

what would u be able to tell me about that?

And yes the engine runs fine when i crank it on, drive it not even a 1/2 mile and it starts the bogging problem, Also remember the guy read a Misfire code and its popped up once more,

[60dgrzbelow0]

BigBoi...

In regards to the transmission's ill-behaviour:

Have a look at this link on the 2001 Buick Century... further down in the text, in one section it mentions the following interesting information that might answer your question about why the car suddenly down-shifts at highway speeds.:

http://autos.msn.com/research/vip/Reliability.aspx?year=2001&make=Buick&model=Century

Occasional problems on this vehicle are failures of the Transmission Pressure Control Solenoid (PCS) and the connections at the Transmission Pass-Thru Connector. Failure of the Transmission PCS is identified in TSB # 00-07-30-002B. Failure of the connections at the Transmission Pass-Thru Connector is identified in TSB # 02-07-30-022B. The cost to repair the Transmission PCS is estimated at $45.61 for parts and $273.00 for labour. The cost to repair the Transmission Pass-Thru Connector is estimated at $10.00 for parts and $65.00 for labour. All prices are estimates based on $65.00 per flat rate hour and do not include diagnostic time or any applicable sales tax.

[95SleeperAcheiva]

I'm leaning with sappy. Those cats can be a hard catch. How well does it free rev? If you can get it to bog during free rev, drop the front pipe at the manifold and then try free reving again. If she spools up and don't bog with the open exhaust, change the converter. Then hurry up and find out what clogged the converter, because they dont clog by themselves.

The trans kicking down could be because the ecu is detecting high load from a clogged exhaust.

[bigboi407]

the PCS Sounds like the culprit, it doesnt do the HARD shifting where others describe it feels like the transaxle is rocking with every shift, but as for the rest its dead on, and i even told her it feels like a valve isnt doing its job..... the acceleration shudder happens Badly, Say if we drive parking garage when going up to the next level it shudders not hard, just a constant shudder that cannot be mistaken by anyone with any knowledge in mechanics.

Could i change this valve myself, easily? ive rebuilt my spare 5 speed transmission and am confident i could knock this out if need be, im willing to bet Getting to the transmission is gonna be more of pain than actually replacing the valve