2001 Buick Century 3.1 66k miles, Very sluggish

[TGP37]

Check the plastic hose that runs to the back side valve cover. If that comes loose, the engine will draw unmetered air and run lean. And you will hear the vacuum leak.

Check fuel pressure, you may have a dying pump. One way to tell is to put it in park and floor it so the engine bounces off the rev limiter. After 2 or 3 bounces it may start to bog down.......low fuel pressure.....probable clogged filter or bad pump. But idealy you want to check pressure at the Schrader Valve with a rental gauge.

Some people will tape the pressure gauge to the windshield and test it while driving to see if the pressure is failing under load.


If you ever had changed a fuel filter that was partly/mostly clogged, anticipate a dead/dying pump.




Also, this just came to mind.......check spark plug cables. Removing used cables will often break them and the resistance skyrockets. The engine will idle fine under the weak spark but the spark will arc to the block if the cable is busted due to resistance. Use a multimeter and check the cables for resistance.

[95SleeperAcheiva]

Get rid of the Bosch +4s, as they are TERRIBLE in this engine. Replace them with just standard AC Delco plugs for your car, and I bet many of your problems will disappear.

Ditto!

[bszopi]

Get rid of the Bosch +4s, as they are TERRIBLE in this engine. Replace them with just standard AC Delco plugs for your car, and I bet many of your problems will disappear.

[60dgrzbelow0]

BB...

How are your Spark Plug Wires arranged...looms holding them in place ok? ,,,and not hitting anything hot from the exhaust to cause a direct short? This may sound crazy... and OT (Off Topic) ...but ...FWIW...after not being able to get the proper separation of each wire via standard looms and even speciality looms. to prevent the sympathetic radio interference and strange misfires on my '93 LT-1...I finally tried using a handful of very large ZipTies and sort of rigged my own separators between wires. with one around the body of each wire and two sort of "chain-linked" in between and that absolutely eliminated the problem in a very cheap and reliable manner. No matter how much or in whatever way they can be moved around under the the hood and around the engine...the wires cannot come close enough to cause any more problems.

[Merc6]

Yes you have LG8 engine.

3.1 liter V-6 VIN "J"

[bigboi407]

Took it to AZ today got another code Read... EGR Fail, so i bought another one, and swapped it out, THEN

today i have pulled ultimate retard move, i confused the wires and now it wont crank on........ im retarded when it comes to wiring per firing order

Can someone please tell me where i run the wires from the coil pack numbered 1-4-6-3-2-5

Cylinder numbers are

Back
1-3-5
x
2-4-6
Front

^ Correct? Which 3100 am i working on lg8? Firing Order 1-2-3-4-5-6?


how would the cylinder numbers wire to the coil pack? Like 2 doesnt go to 2 on the pack and 3 doesnt go to 3 on the pack so how does it go? i need to get this figured out ASAP as this is the only transportation we have at the moment, call me retarded if youd like XD

EDIT: She has now called me retarded because i cant figure out the order in which the plugs go

[bigboi407]

As you have observed, transmission work is always a long road with no turns in it... Have a look at these generic videos to get an idea of the PCS hardware design and functionality as well as the complexity in the diagnoses and repairs that may ensue. I am not very familiar with the transmission/transaxle arrangement in the "East-West" FWD engine layouts but others here can counsel you on whether or not the biggest problem has to do with gaining access to the tranny's innards b4 you can even replace such a simple solenoid device:

http://www.youtube.com/watch?v=2UAeYUtc1hA

http://www.youtube.com/watch?v=OGckmJK2rNQ

http://www.youtube.com/watch?v=JUSSj_2eHUY

http://www.youtube.com/watch?v=dkLQpezVk9I&feature=related

There may be another culprit here: The TPS (Throttle Position Sensor) may be out of sync or failing and give some jumpy signals to the PCM that will cause that bizarre shifting phenomena. Take a peek at THIS video for an example:

http://www.youtube.com/watch?v=f3nfayKOvsQ&feature=related

PS..."Yeah...Now about those TPS Reports... Did you get the Memo about putting on the new Cover Sheets?"

http://www.youtube.com/watch?v=Fy3rjQGc6lA

looks like ima have to skip gettin my feet wet and just jump in head first... Thank you for the info provided along with everyones input, once i get some time to myself ill look over all the info

[60dgrzbelow0]

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

As you have observed, transmission work is always a long road with no turns in it... Have a look at these generic videos to get an idea of the PCS hardware design and functionality as well as the complexity in the diagnoses and repairs that may ensue. I am not very familiar with the transmission/transaxle arrangement in the "East-West" FWD engine layouts but others here can counsel you on whether or not the biggest problem has to do with gaining access to the tranny's innards b4 you can even replace such a simple solenoid device:

http://www.youtube.com/watch?v=2UAeYUtc1hA

http://www.youtube.com/watch?v=OGckmJK2rNQ

http://www.youtube.com/watch?v=JUSSj_2eHUY

http://www.youtube.com/watch?v=dkLQpezVk9I&feature=related

There may be another culprit here: The TPS (Throttle Position Sensor) may be out of sync or failing and give some jumpy signals to the PCM that will cause that bizarre shifting phenomena. Take a peek at THIS video for an example:

http://www.youtube.com/watch?v=f3nfayKOvsQ&feature=related

PS..."Yeah...Now about those TPS Reports... Did you get the Memo about putting on the new Cover Sheets?"

http://www.youtube.com/watch?v=Fy3rjQGc6lA

[bigboi407]

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.

Thanks for the input, my honest opinion is that it may be Quite a few problems ALL adding up to give me the problems i currently have, i will take video of the free rev and also video of the bog, TODAY because i wanna get this over with.. Free rev it does bog BUT only on High RPM's and its intermitten not Every time i touch the gas pedal(Will Double Check to confirm), when driving it only does it on Low RPM's and throws a misfire code, i dont believe that a clogged cat could cause the engine to throw a misfire code, or is that possible??

its also running hotter than average, would the bosch +4 plugs have anything to do with that? ive read that some people have problems and others say theyre wonderful plugs, i changed the plugs AFTER the seafoam, i like bosch over cheap brands anyday, i run em in my civic i and i didnt notice much difference versus the old plugs it had.

[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

[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.

[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.

[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,

[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 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?