Regal chugging and hesitation during acceleration

[Enslow]

Oh and I'm still not logging any misfires. The throttle position shows as % rather than voltage on my scanner but it seems to be functioning properly. I'll keep testing.

Is there a way to disable the TCC lockup?

I just wanted to share what I learned about logging missfires when I was diagnosing a similar issue on my 1999 LeSabre. The computer will only log missfires if it sees a certain number of consecutive misfires on one cylinder. I had random misfires that caused bad chugging under a light load, but no logged misfires. I caught the misfires by monitoring them in real time. Then I saw thousands of misfires while it was chugging. Being random, and not consecutive for long enough, the computer didn't log them. When I removed the old wires and plugs, they were so bad I'm surprised the computer didn't log it.

See if your blutooth can view misfires in real time and see what you get.

 

[HotZ28]

Good thought Enslow, and you are right. I should have made that clear earlier. Anyway, the OP said he has changed the wires & plugs, so there must be something else causing this. Going back a few post, I noticed that he said the engine would not start one morning until he opened the T/B. That sounds like it may be flooded with gas, which could be the result of a failed fuel pressure regulator. This is worth checking into also. Just because the S/C is not as likely to fail as the plastic, does not mean that the fuel pressure regulator is any different than those mentioned. Pull the vacuum line to the regulator and look, or smell for the presence of raw fuel.

Report Date : January 22, 2014 at 03:31 PM
NHTSA Action Number : EA02030

NHTSA Action Number : EA02030 NHTSA Recall Campaign Number : 04V090000
Vehicle Make / Model: Model Year(s):
BUICK / LESABRE 1996-2002
BUICK / PARK AVENUE 1996-2002
BUICK / REGAL 1996-2002
BUICK / RIVIERA 1996-2000
CHEVROLET / IMPALA 2000-2002
CHEVROLET / LUMINA 1998-1999
CHEVROLET / MONTE CARLO 1998-2002
OLDSMOBILE / 88 1996-2000
OLDSMOBILE / 98 1996-2000
OLDSMOBILE / INTRIGUE 1998-1999
PONTIAC / BONNEVILLE 1996-2002
PONTIAC / GRAND PRIX 1997-2002
Manufacturer(s) :
General Motors LLC
Component(s) :
FUEL SYSTEM, GASOLINE
FUEL SYSTEM, GASOLINE😀ELIVERY
FUEL SYSTEM, GASOLINE😀ELIVERY:HOSES, LINES/PIPING, AND FITTINGS
Date Investigation Opened : October 22, 2002
Date Investigation Closed : March 9, 2004
Summary:
EA02-030 IS CLOSED WITH GMEA02-030 IS CLOSED WITH GM¿S ACTIONS IN 03V-473 AND 04V-090 RECALLING APPROXIMATELY 529,000 MY 1998-99 C- AND H-BODY VEHICLES EQUIPPED WITH DEFECTIVE FUEL PRESSURE REGULATORS. THESE VEHICLES WERE EQUIPPED WITH PLASTIC INTAKE MANIFOLDS THAT ARE UNABLE TO CONTAIN PRESSURES THAT OCCUR IN SOME BACKFIRE EVENTS AND DEFECTIVE FUEL PRESSURE REGULATORS WITH LEAKING DIAPHRAGMS THAT CAN PROVIDE A SOURCE OF FUEL TO PRODUCE A COMBUSTIBLE AIR-FUEL MIXTURE IN THE MANIFOLD. THE CLOSING OF THIS INVESTIGATION DOES NOT CONSTITUTE A FINDING BY ODI THAT NO SAFETY DEFECT EXISTS IN THE VEHICLES THAT ARE NOT INCLUDED IN GM¿S RECALLS. ODI WILL CONTINUE TO MONITOR THE INCIDENCE OF MANIFOLD RUPTURES AND RELATED FIRES IN OTHER MY 1995-2002 GM PASSENGER CARS EQUIPPED WITH THE SUBJECT INTAKE MANIFOLD. FOR ADDITIONAL INFORMATION, SEE THE ATTACHED CLOSING REPORT.

 

[Enslow]

I agree that the FP regulator is a likely possible cause, and is easy to check as you say. My only thought was that the replacement wires may be bad, or the coils may be failing, However, I think I'd expect coils would cause a more consistent miss which would cause the misses to be logged.

 

[HotZ28]

I agree that the FP regulator is a likely possible cause, and is easy to check as you say. My only thought was that the replacement wires may be bad, or the coils may be failing, However, I think I'd expect coils would cause a more consistent miss which would cause the misses to be logged.

Replacement "cheap" wires are defiantly a concern, which was previously mentioned. When the coils fail, they can either develop weak spark, or no spark. No spark, is much easier to troubleshoot. Weak spark may not show misfire for an extended period of time, not long enough to set a Hard code for misfire. With my Matco scanner, I can watch real-time misfire & logs, as well as the accumulated and timed misfire data.

 

[cckeeler]

The scanner that I have been using is a bluetooth OBD2 adapter in conjunction with the "torque" app on my phone. I have watched the real time misfire log on all 6 cylinders as the car is doing it and it doesn't show any misfires. I was concerned about whether or not it was actually working because it didn't show anything so I unplugged one of the fuel injectors and the thing started showing misfire after misfire. Granted this is not an expensive scanner by any means, but from what it shows I am not actually misfiring. So I guess I just moved on from the misfire theory and started investigating other areas.

Now, to be honest, I have been a bit preoccupied as I tried changing the cv axle on my wife's volkswagen and it has absorbed my last 4 days so I haven't had much chance to mess with the Buick (It was rusted inside the transmission and wouldn't come out). I will take a look at the pressure regulator in the morning to check for fuel in the vacuum hoses. I am going out of town until Sunday but am planning on getting the catalytic converter checked out on Monday. I will report back. While I'm at it, is there a way to check the fuel pump other than fuel pressure? I checked it and at idle and it checked out.

Thanks guys for all the help. We have checked off a couple things from the list but I am extremely anxious to finally get this thing figured out.

 

[HotZ28]

While I'm at it, is there a way to check the fuel pump other than fuel pressure? I checked it and at idle and it checked out.

With a good pump, the fuel pressure may not show regulator leakage. Follow the previous suggestions on how to determine leaks in the regulator.

 

[cckeeler]

sounds good. I will report in the morning. Too dark for me to do a thorough look see tonight. thanks

 

[bigsky]

I cleaned the MAF in a 2000 PA and it started "chuggling" at around 45mph.

Did an internet search and found out about the "chuggling" [chuggle] as GM refers to it. In my case I could unplug the MAF and the problem was gone.

I did find a piece of advice that worked for me and has worked for others as well.

DISCONNECT THE BATTERY (some say negative, some say both), for 30 minutes (some say overnight).

This RESETS something in the computer on shift points or something. [this age of "computer glitches"]

Anyways, all I can say is it WORKED for me, I think I disconnected the negative for a couple of hours.

The good thing is, no cost to try it. I had bought a new and fairly expensive MAF, but never put it in.

 

[Enslow]

HotZ28,
Correct me if I'm wrong, but a misfire reported by the computer (real time or logged) can be caused by ignition failure, or an improper air fuel mixture that will not combust properly. Therefore, chugging caused by a leaking fuel pressure regulator, vacuum leak, faulty EGR, or any system controlling the air fuel ratio should show up as a misfire, should it not?

If the above is true, then, because he did not observe engine misfires while it was chugging and jerking, this would suggest some non-engine management issue. The 4T65e transaxle was known to have issues with the shift solenoids, and especially the pwm solenoid. However, I thought that mostly affected the 1- 2 shift, as it did in my case.

If I'm wrong on this, especially the misfire, feel free to educate me.

 

[HotZ28]

Correct me if I'm wrong, but a misfire reported by the computer (real time or logged) can be caused by ignition failure, or an improper air fuel mixture that will not combust properly. Therefore, chugging caused by a leaking fuel pressure regulator, vacuum leak, faulty EGR, or any system controlling the air fuel ratio should show up as a misfire, should it not?

Cylinder misfire is more common with a lean mixture, but if the the mixture is too rich (too much gasoline) due to extra fuel being dumped into the intake, misfire would not be as likely. This event tends to occur in all cylinders, not just one. Again, misfire would have to be detected in real time rather than misfire logs or the P0300 code.

 

[cckeeler]

So if the fuel pressure regulator is leaking or faulty, would I see a misfire while viewing real-time data? With me seeing no misfires I wonder if I am chasing an engine problem when one doesn't exist.

 

[Enslow]

A leaking fuel filter would enrich the mixture. So to clarify, according to Hotz the stumbling due to enrichment may not cause misfires. If it's that bad, you should smell gas in the vacuum line to the FP regulator. It's really quick and easy to do, and should be checked. Let us know.

 

[cckeeler]

Yeah checked yesterday and I could see any fuel in the vacuum hose of the fuel pressure regulator.

 

[cckeeler]

Alright guys, I'm at a loss so I thought I would recap what has been done and what we have eliminated due to testing. Correct anything I have wrong:

1) unplugged MAF (no difference)
2) replaced spark plugs and wires (no difference)
3) replaced fuel filter (No Difference)
4) Check fuel pressure at idle (showed around 48 psi)
5) Cleaned throttle body and EGR valve (No difference)
6) Checked for fuel in Fuel Pressure Regulator (No fuel evident)
7) Scanner shows no misfires during the chugging and jerking
8) No codes (Except for the EGR valve hasn't come on for quite some time)
9) Still chugs and jerks in "3" like it does when in normal "D" (I was under the impression this eliminated the TCC, but unsure)


The only other test I haven't performed in that of the catalytic converter which is next on my list. I have been having so many other car related issues with my other car I haven't been able to give much time to this buick. I am really hoping to wrap this thing up this week or take it into a shop to see what they say.

Also the attached photo is from the app I used to scan my computer. This is what my 1st o2 sensor looks like on my scanner. Are those sensors supposed to be so sporadic?

 

[cckeeler]

One more comment....

I noticed there was a TCC slip option on my scanner. While watching that the chugging, hesitation, jerking, whatever, would start when the slip dropped to almost nothing. To me this indicates that it is actually locking up. It doesn't really bounce around once it locks up until I give it a significant amount of gas.

If this is the case, would this indicate that the car simply doesn't have the power to maintain that TCC lock up?

I'm just fishing here.

 

[Enslow]

Unless I'm mistaken, the TC locks up in both 3 and D. If you were able to keep the brake switch closed so the brake lights are on full time (just for a test drive), this should prevent the TC from locking up. This should prevent the TC from engaging at all, which should prevent any slippage. If the TC is causing your chugging, it should completely disappear with the brake switch closed.

I wouldn't leave it like that, only for a test drive.

 

[Devast8sjl]

When testing the coils primary resistance, use a paper clip to insert into the primary side terminals..

Sorry HotZ28 but respectfully, this was bad advise to suggest using paperclips. The female slots on the coil pack have a tempered "hook-style" tab inside that I could feel "lock-on" to the paperclip when I slid it into the terminal. I knew right away I had a big problem. It was virtually impossible to get that tab depressed enough to get the clip to come out without bending the tab inside the coil pack. A spade connector like the ICM has would be the preferred aid for this test.

 

[Elpoosy]

Hey Guys, I'm experiencing the EXACT same issues that OP is having and i'm wondering if there was ever any resolve to this issue? I've replaced a few bad vacuum lines and had my transmission professionally tested and serviced but have not yet found what is causing the issue. The transmission shop told me that it seems to be an odd issue in the way that no codes are being thrown by the transmission but by messing with the TC lock-up, they can get it to go away.

I personally still think that the torque converter is going bad but the issue is so random and untelling that it makes me wonder if its not something simple that is being overlooked like the MAF or bad fuel sending unit. The problem will show itself for a week straight and be extremely active and then go away for two weeks displaying a car with no issues at all. this is VERY FRUSTRATING!

So in recap, OP, Did you find out what was causing this issue?

 

[smatchimo]

also looking for an update. my 95 regal is experiencing this hessitation and I am about to replace all the transmission solenoids, as I have an issue with the transmission not shifting down into first when coming to a stop (sometimes) is an intermittent issue. Another is while driving on free way I feel like the car is a bit slugggish on throttle and if i go up a slight hill the car will kick down into third and and be stuck there.

 

[G-653058]

Well in that case, let's forget about the TCC, or trans and focus on some other things previously mentioned. Have you had the CAT back pressure tested? Have you tried driving with the gear selector in 3rd with the MAF disconnected?

Engine mounts and trans mounts mb.