What advice on engine shaking should I follow first?..94 LaSabre
1994buick
09-18-2005, 11:46 PM
My engine is shaking when driving between 45 and 60 miles per hour.
It does it sometimes.....and then it topped doiung that yesterday and this morning. Now it does it again this evening. It is not subtle shaking when it happens....it is serious shaking.
So far I have had these things told to me.
#1 Opinion:
One independant shop mechanic (NOT a Buick shop ) said I need a new transmission because of this shaking. He also reported he noticed low pressure (I think the word was pressure) on the #5 cyclinder when he was trying to find out why the car engine shakes. he replaced the spark plugs.
#2 Opinion:
A man on this website suggests that the shaking could be caused by a
vacuum leak.
#3 Opinion:
The local Buick dealer service dept gave it a computer diagnosis and looked at it...They get a 02 sensor code...and say the shaking is caused because there is a problem in the fuel injector wiring. They say a signal is not going between the 5th cyclinder fuel injector and the Power Control Module. The Buick dealer says they will have to spend an hour or two locating the wire...and maybe replace the Pwr Cntrl Module
#4
A relative of mine, retired from GM as a Service Manager for a whole section of the US....drove the car and says it is not a transmission problem. He called a service manager in milwaukee for input. They told me to First replace the 02 sensor. If that does not solve it....I should have the fuel injectors cleaned at a GM shop...because they only do the job right.
?????
What direction should I be looking in? i know nothing about cars....and can't afford experimentation. I surely am glad I didn't let the independant shop replace the transmission , or the Buick dealer replace the power module for $525.00.....on a hunch.
It does it sometimes.....and then it topped doiung that yesterday and this morning. Now it does it again this evening. It is not subtle shaking when it happens....it is serious shaking.
So far I have had these things told to me.
#1 Opinion:
One independant shop mechanic (NOT a Buick shop ) said I need a new transmission because of this shaking. He also reported he noticed low pressure (I think the word was pressure) on the #5 cyclinder when he was trying to find out why the car engine shakes. he replaced the spark plugs.
#2 Opinion:
A man on this website suggests that the shaking could be caused by a
vacuum leak.
#3 Opinion:
The local Buick dealer service dept gave it a computer diagnosis and looked at it...They get a 02 sensor code...and say the shaking is caused because there is a problem in the fuel injector wiring. They say a signal is not going between the 5th cyclinder fuel injector and the Power Control Module. The Buick dealer says they will have to spend an hour or two locating the wire...and maybe replace the Pwr Cntrl Module
#4
A relative of mine, retired from GM as a Service Manager for a whole section of the US....drove the car and says it is not a transmission problem. He called a service manager in milwaukee for input. They told me to First replace the 02 sensor. If that does not solve it....I should have the fuel injectors cleaned at a GM shop...because they only do the job right.
?????
What direction should I be looking in? i know nothing about cars....and can't afford experimentation. I surely am glad I didn't let the independant shop replace the transmission , or the Buick dealer replace the power module for $525.00.....on a hunch.
HotZ28
09-19-2005, 09:46 AM
You have a lot of opinions so far, so I will give you something else to think about!
:iceslolan
http://www.buickforums.com/forums/showthread.php?t=1446
#1 Opinion: Do not agree
#2 Opinion: Possible
#3 Opinion: Possible
#4 Opinion: Do not agree that only a GM dealer can clean injectors.
O2 sensor possible but not likley to cause missfire!
:banghead: :lol2:
:iceslolan
http://www.buickforums.com/forums/showthread.php?t=1446
#1 Opinion: Do not agree
#2 Opinion: Possible
#3 Opinion: Possible
#4 Opinion: Do not agree that only a GM dealer can clean injectors.
O2 sensor possible but not likley to cause missfire!
:banghead: :lol2:
padriver
09-19-2005, 01:49 PM
Another idea: The EGR valve
I have a 94 Park Avenue which recently had similar symptoms. It badly misfired, and the shudder was especially noticeable at low rpms in O/D, about the same speed range as you stated.
The scan tool showed random misfiring among all cylinders, so I first thought it had to be the powertrain control module or the ignition coils.
However, another thing the scan tool showed was a weird behavior of the EGR valve. The actual position of the valve would jump all over the place, it would not stay at the position that was commanded by the PCM. The actual valve position constantly changed. As I found out, this condition does not necessarily throw a code.
I disabled the EGR valve by removing the electrical connector, and the engine ran fine. No misfiring, no shudder - nothing.
My car has now a new EGR valve and runs great again.
I have a 94 Park Avenue which recently had similar symptoms. It badly misfired, and the shudder was especially noticeable at low rpms in O/D, about the same speed range as you stated.
The scan tool showed random misfiring among all cylinders, so I first thought it had to be the powertrain control module or the ignition coils.
However, another thing the scan tool showed was a weird behavior of the EGR valve. The actual position of the valve would jump all over the place, it would not stay at the position that was commanded by the PCM. The actual valve position constantly changed. As I found out, this condition does not necessarily throw a code.
I disabled the EGR valve by removing the electrical connector, and the engine ran fine. No misfiring, no shudder - nothing.
My car has now a new EGR valve and runs great again.
Bassasasin
09-20-2005, 09:12 AM
Bad shaking can be alot of stuff..
Minor shaking. Steering wheel.. etc.. how bout a CV joint cuff?
Or bad tire or tires.
There is a known problem with the Clutch lock control valve (trans).. leaking and not locking firm the clutches in the transmission. This shaking is usually in transition between the higher gears. They call it "chuggle"..I notice it when it wants to downshift going about 54 mph and going up hill.
Didnt want to miss those.
You mentioned not knowing much.. that costs $$
Good Luck.
Minor shaking. Steering wheel.. etc.. how bout a CV joint cuff?
Or bad tire or tires.
There is a known problem with the Clutch lock control valve (trans).. leaking and not locking firm the clutches in the transmission. This shaking is usually in transition between the higher gears. They call it "chuggle"..I notice it when it wants to downshift going about 54 mph and going up hill.
Didnt want to miss those.
You mentioned not knowing much.. that costs $$
Good Luck.
1994buick
09-22-2005, 03:28 AM
You have a lot of opinions so far, so I will give you something else to think about!
:iceslolan
http://www.buickforums.com/forums/showthread.php?t=1446
#1 Opinion: Do not agree
#2 Opinion: Possible
#3 Opinion: Possible
#4 Opinion: Do not agree that only a GM dealer can clean injectors.
O2 sensor possible but not likley to cause missfire!
:banghead: :lol2:
Still have not solved problem. Mechanic had it yesterday and of course the car would not shake. He want to look at all the wires...but says it has to be right after an episode of shaking. So...I took it home until I can bring it back shaking.
I drove around quite a while without any problems... But in the evening...i went driving about 10 miles out of town to my daughter's..... No shaking..no problem. Serv Light onas it usually is. (BTW AutoZone can't get a reading on it) On the way back home a few hours later I drobve about 6 milkes with no shaking...THEN without warning...car stalled at about 40 moh. I pulled to side of road . Restarted the car almost immediately....and had no problem driving the last 5 miles home. This must be related to whatever is causing the shaking (when it happens). any new ideas?
I has gotten a new alternator last month...new plugs last week. New spark plug wires were tried...to no avail. Mechanic say no vvacuumn leak.he says transmission fluid looks clean. He say he cleaned the fuel injector the other day when i first showed him the shaking.
I wonder if just getting a replaced PCM might fix it...because that was something the Buick dealer was saying would be the "worst case scenario".
By now it's very obvious that I am not a car buff. i didn't mind driving it around trying to get it shaking so the mechanic can try to find the wiring problem... because I could sort of control that by slowing down.. But ...it is pretty dangerous to have a car just stall at 40 mph.
:iceslolan
http://www.buickforums.com/forums/showthread.php?t=1446
#1 Opinion: Do not agree
#2 Opinion: Possible
#3 Opinion: Possible
#4 Opinion: Do not agree that only a GM dealer can clean injectors.
O2 sensor possible but not likley to cause missfire!
:banghead: :lol2:
Still have not solved problem. Mechanic had it yesterday and of course the car would not shake. He want to look at all the wires...but says it has to be right after an episode of shaking. So...I took it home until I can bring it back shaking.
I drove around quite a while without any problems... But in the evening...i went driving about 10 miles out of town to my daughter's..... No shaking..no problem. Serv Light onas it usually is. (BTW AutoZone can't get a reading on it) On the way back home a few hours later I drobve about 6 milkes with no shaking...THEN without warning...car stalled at about 40 moh. I pulled to side of road . Restarted the car almost immediately....and had no problem driving the last 5 miles home. This must be related to whatever is causing the shaking (when it happens). any new ideas?
I has gotten a new alternator last month...new plugs last week. New spark plug wires were tried...to no avail. Mechanic say no vvacuumn leak.he says transmission fluid looks clean. He say he cleaned the fuel injector the other day when i first showed him the shaking.
I wonder if just getting a replaced PCM might fix it...because that was something the Buick dealer was saying would be the "worst case scenario".
By now it's very obvious that I am not a car buff. i didn't mind driving it around trying to get it shaking so the mechanic can try to find the wiring problem... because I could sort of control that by slowing down.. But ...it is pretty dangerous to have a car just stall at 40 mph.
stuzman
09-22-2005, 10:59 AM
Still have not solved problem. Mechanic had it yesterday and of course the car would not shake. He want to look at all the wires...but says it has to be right after an episode of shaking. So...I took it home until I can bring it back shaking.
I drove around quite a while without any problems... But in the evening...i went driving about 10 miles out of town to my daughter's..... No shaking..no problem. Serv Light onas it usually is. (BTW AutoZone can't get a reading on it) On the way back home a few hours later I drobve about 6 milkes with no shaking...THEN without warning...car stalled at about 40 moh. I pulled to side of road . Restarted the car almost immediately....and had no problem driving the last 5 miles home. This must be related to whatever is causing the shaking (when it happens). any new ideas?
I has gotten a new alternator last month...new plugs last week. New spark plug wires were tried...to no avail. Mechanic say no vvacuumn leak.he says transmission fluid looks clean. He say he cleaned the fuel injector the other day when i first showed him the shaking.
I wonder if just getting a replaced PCM might fix it...because that was something the Buick dealer was saying would be the "worst case scenario".
By now it's very obvious that I am not a car buff. i didn't mind driving it around trying to get it shaking so the mechanic can try to find the wiring problem... because I could sort of control that by slowing down.. But ...it is pretty dangerous to have a car just stall at 40 mph.
Here's some of my thoughts...you mentioned that an independent garage found a problem on #5 cylinder and you mentioned pressure. You didn't mention if he was checking the pressure drop across the injector or the compression for the cylinder. Later, you mentioned that the dealer found some problem with the injector for the #5 cylinder. So, I would focus on this cylinder and take a closer look at the injector circuit. If it turns out to be a problem with this injector, then it could be the injector, wiring or the PCM. Just some food for thought...
I drove around quite a while without any problems... But in the evening...i went driving about 10 miles out of town to my daughter's..... No shaking..no problem. Serv Light onas it usually is. (BTW AutoZone can't get a reading on it) On the way back home a few hours later I drobve about 6 milkes with no shaking...THEN without warning...car stalled at about 40 moh. I pulled to side of road . Restarted the car almost immediately....and had no problem driving the last 5 miles home. This must be related to whatever is causing the shaking (when it happens). any new ideas?
I has gotten a new alternator last month...new plugs last week. New spark plug wires were tried...to no avail. Mechanic say no vvacuumn leak.he says transmission fluid looks clean. He say he cleaned the fuel injector the other day when i first showed him the shaking.
I wonder if just getting a replaced PCM might fix it...because that was something the Buick dealer was saying would be the "worst case scenario".
By now it's very obvious that I am not a car buff. i didn't mind driving it around trying to get it shaking so the mechanic can try to find the wiring problem... because I could sort of control that by slowing down.. But ...it is pretty dangerous to have a car just stall at 40 mph.
Here's some of my thoughts...you mentioned that an independent garage found a problem on #5 cylinder and you mentioned pressure. You didn't mention if he was checking the pressure drop across the injector or the compression for the cylinder. Later, you mentioned that the dealer found some problem with the injector for the #5 cylinder. So, I would focus on this cylinder and take a closer look at the injector circuit. If it turns out to be a problem with this injector, then it could be the injector, wiring or the PCM. Just some food for thought...
Alibi
09-23-2005, 10:18 AM
That sounds an awful lot like a bad ignition control module. I had one go bad on my '90 olds 88 (3.8L Vin C) and the engine would shudder if I accelerated from about 55 to 70. I never had it stall though.
The easy way to see if it is bad is to remove the long electrical connector and see if there is any grey goo coming from the inside. Also, you could remove it and have it tested at autozone for free (3 11mm bolts hold it on) after you take the coils off.
My :2cents:
The easy way to see if it is bad is to remove the long electrical connector and see if there is any grey goo coming from the inside. Also, you could remove it and have it tested at autozone for free (3 11mm bolts hold it on) after you take the coils off.
My :2cents:
sexystud689
11-09-2005, 02:40 PM
I have the same shaking problem with my 95 lesabre, I think its not at speeds but at a certain rpm, but my 95 doesnt have a tachometer so i cant test that hypothesis. It might just be the engine "bogging down" because the transmission doesnt shift, i dont know how to fix it but if you guys can help thanks
ChemMan
11-22-2005, 05:23 PM
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