acceleration problem+sound

Hi guys, I own a 2002 Buick Regal LS with the 3800 series II not supercharged and I just love the car.. Driving normally, the car works fine but when I tried to pass car by accelerating, the car hesitates a little bit so yesterday, I did a test:

I floored the accelerator when I was at 20 km/h.. everything here's normal

approximately at 4500 rpm, the car seems to hesitate a bit to accelerate but still is accelerating..

once at 5000rpm, there was my biggest shock: acceleration is sooo poor and at that rpm, I can hear from under the hood or under the car and "tic tic tic tic tic tic tic" very loud and very fast..same as if you could hear the spark on the plugs!! Also, it seems that the car is running on 5 or 4 cylinders at that 5000 rpm + more. Its the first time I tried it..

once it finished to accelerate, the car shifts to second gear.. but I didnt tried it on the second gear! Like I told you, on normal driving the car works very good but I did the test because I tought the car wasn't accelerating normally and looks like I was right.. need help thanks!

and the mileage on the car: 78 800 km

Might be a bad CAT GM has a bad problem with 01-02 cars. Did you ever get a letter in the mail from GM if not someone around here has it.

Might be a bad CAT GM has a bad problem with 01-02 cars. Did you ever get a letter in the mail from GM if not someone around here has it.


yeah sure I received the letter for the Catalyser thing! The letter is still in the glovesbox.. tell me please, what is a Catalyser and what does it do on a car?! I'm good with mechanics but there's a lot of things I don't know yet!

For you, it seems the problem?! For example, if my CAT doesn't work good, the symptoms could be the ones I have with the car?!

yes it could be the problem if the CAT plugs it slows the flow of exhaust and then the engine can not operate properly. If you can't the air out that the engine sucked in it will not run right. Its kind of like putting a kink in your garden hose the water slows up and the pressure builds up in the hose.

here is a good link with some info and pictures. http://auto.howstuffworks.com/catalytic-converter.htm

Troy

A big thank you Troy! Very very interesting informations there :D

Last question, I'm not a bif fan of dealers, but if my service engine soon light or vehicule service soon light isn't "on" could it still be the problem?

Well if it is the CAT GM will replace it FREE but it has to be a GM CAT and installed at a GM dealership. It is possible there is no SES light some parts stores will scan your car for codes for free.

I agree with Troy1. CAT is a high probability. I have the same notice sitting in the glove box in my '01 Regal GS. The first time I get any misfires or any driveability probelms with or without SES light I am definitely going to take it to the dealer and take advantage of GM's offer before it causes any damage.

but if there's no light "on" and they put the scan on the car, there'll be no code right? so they won't change the CAT for no reason?!?

Like I said, during normal driving, the car is number 1 but when on acceleration passing 4000rpm, the car sucks... are they going to try my car on the road at 4000 rpm or just around at 2000rpm? Because I believe that if im telling them the car's symptons et they check rapidly, they'll tell me there's nothing wrong with the car!

but if there's no light "on" and they put the scan on the car, there'll be no code right? so they won't change the CAT for no reason?!?

Like I said, during normal driving, the car is number 1 but when on acceleration passing 4000rpm, the car sucks... are they going to try my car on the road at 4000 rpm or just around at 2000rpm? Because I believe that if im telling them the car's symptons et they check rapidly, they'll tell me there's nothing wrong with the car!

Troy1 and I have been discussing the issue of CATs. See link below:

http://www.automotiveforums.com/vbulletin/showthread.php?t=506028

Any GM dealer has the capability to perform tests on the exhaust system for excessive backpressure or a clogged CAT, etc. regardless of whether the PCM is throwing any codes or triggering a SES light.

Flaky CATs on 2001 - 2002 is a known problem so that is the best starting point.

yesterday I tried to accelerate and finally the check engine soon light came on... but only blinking!! when i took my foot of the accelerator, 10 secs later, the light went back off! anyway, I took an appointment with my dealer! Just hope that's it!

yesterday I tried to accelerate and finally the check engine soon light came on... but only blinking!! when i took my foot of the accelerator, 10 secs later, the light went back off! anyway, I took an appointment with my dealer! Just hope that's it!

That is a good decision. When SES blinks that indicates the PCM has detected a true misfire condition. Let us know how it turns out. Good luck!

Definately pursue the CATALYTIC converter path, but also check your plugs and wires. My PA was doing the same thing a couple weeks ago and it did eventually throw a 'random misfire' code. I did a tune up and sure enough the ceramic insulation on the cylinder 3 plug was cracked. Also, if you are hearing a tic you may have a 'jumping spark' as I call it. Start the engine at night and listen and look. Try to pinpoint the sound and try to see it you see the spark jumping to any nearby ground points - you may have to rev the engine to produce similar conditions. Also if you happen to lean on any metal under the hood and you get a jolt - you may have found your problem. Bottom line - it's just something to look into and I've seen it in the past. Definately inspect(replace) the plugs and wires. It only takes a little bit of time. Let me know what turns up. M

Okay, I'm back in my office but before beginning my work, I wanna tell you that I went to the dealer at first time in the morning! They inspected my car, did their diagnostics and turns out it was the CAT!! They changed it at no cost like GM's letter was telling me! I had 1.1 lbs pf pressure at 2000 rpm and the muffler's end and they told me that usually, reffering to Buick's book, its about 3 lbs of pressure there!! They changed the CAT and the car power is back!! No lacking, no sounds whatever the rpm is!! Finally I've got my 200 horsespower back instead of my 100 hp! :P Thanks again guys and if I can help you with anything :D

GOOD! :bigthumb:

I'll second that.

BTW - Do not throw away your notification. If the new CAT ever fails (heaven forbid) before the expiration of the extended warranty you will be entitled to another CAT.

I'll second that.

BTW - Do not throw away your notification. If the new CAT ever fails (heaven forbid) before the expiration of the extended warranty you will be entitled to another CAT.


OOOHHH Good to know thanks :D