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FIXITMAN, Master Technician
Category: Buick
Satisfied Customers: 17326
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Buick Park Avenue: I have a 2000 Buick Park Avenue that shudders

Customer Question

I have a 2000 Buick Park Avenue that shudders when just barely giving enough gas to increase speed. It happens in all gears. If I give it a lot of gas or let off the gas there isn't a problem. Seems to be worse when hot.
Submitted: 2 years ago.
Category: Buick
Expert:  FIXITMAN replied 2 years ago.
Hello, my name is***** for the question. If I am not online when you return please give me some time to get back to you. I know you said that the codes were read, but can you tell me if the check engine light actually comes on when the problem is occurring? Does this happen every time you drive it?
Customer: replied 2 years ago.
No Check Engine Light. No engine codes and no transmission codes (read at transmission service repair center). Doesn't seem to be a problem (or nearly as bad) when cold and it is when hot.
Customer: replied 2 years ago.
I thought it had gotten much better after replacng the engne mounts (and the front one was bad) but it may have been the cooler weather. I bought bargin mounts offline. I might check those again just in case it failed. I'll put in dive with brake held and see how much the engine rises.
Expert:  FIXITMAN replied 2 years ago.
Check the mounts again to make for sure that they are fine. I would also clean out the mass air flow sensor. It is common for this sensor to become dirty and cause this.
Customer: replied 2 years ago.
I cleaned the Mass Air Flow Sensor this evening. I'll see how it does tomorrow.
Expert:  FIXITMAN replied 2 years ago.
Please let me know and we can continue from there.
Customer: replied 2 years ago.

Cleaned Mass Air Flow Sensor, replaced Air Filter as well. Still doing the same thing. When I get up of a morning and leave at 06:00, the outside air temp was 69 - 70 degrees. I get no issues. Going out at lunch with temps around 83 and driving a few miles, it starts to do it again.

Expert:  FIXITMAN replied 2 years ago.
Does your scan tool read live engine data?
Customer: replied 2 years ago.

I have Torque app with wireless obd2. I believe it does read live data. What you want me to look at?

Expert:  FIXITMAN replied 2 years ago.
The main thing I would like to know is what the fuel trim readings are. I want to know what they are at idle and when you are at a cruising speed.
Customer: replied 2 years ago.

Here's some data. Is this what you need? Give me a good email address and I can send you the file.

Time Lat Lon Bearing GPS Speed Speed(mph)Revs(rpm)Boost(psi)LTFT1(%)F/T 1x1(%)STFT1(%)EGR Duty(%)Load(%)MAF(cfm)PC.Sol.Act(Amps)PC.Sol.Ref(Amps)
Expert:  FIXITMAN replied 2 years ago.
Thank you. Have you checked the fuel pressure.
Customer: replied 2 years ago.

I haven't checked it but will. Assuming it is ok, what next?

Expert:  FIXITMAN replied 2 years ago.
If it is fine then from those readingsit is possible that you have a logged catalytic converter in the exhaust.