Does anyone else have this problem on his car?

[rc5]

My old Pontiac Grandam 1986 has a weird problem. If I drive it for 5-10 minutes on freeway, the engine will shake noticably when I stop before the first red light after exiting the freeway. It behaves like a person who just ran 5 miles.

 

[Muadib]

Next time it happens, pop the hood and look at the engine. If it is shaking like it wants to jump out of the car, then you need new motor mounts. When is the last time you had a tune up?

 

[PsychoAndy]

Yeah, i was gonna say, it could be motor mounts. We were talkin aboot them in physics, and your thing reminded me of it.

 

[flot]

Why would his problem suggest motor mounts specifically? I (could be wrong) don't see any connection between driving for 5-10 mins on the freeway and the motor mount issue?

Does it also have a loss of power when starting up from the light? Does the problem go away or get worse with the A/C on or off?

 

[TopGun]

Sounds like you need a good tune-up, do the rpms drop when it shakes? Like it's going to stall?

 

[BDawg]

Sounds like typical 4 cylander shake.

After my miata, I swore to never own another 4 cylander car again.

 

[Ornery]

Sounds like it's misfiring. Could be from one of several different sources. Spark jumping to adjacent terminal, timing off due to loose belt or chain... I'm sure there are other reasons, but putting it on a computer would be a good start. Might as well throw new plugs and wires in there before you do. Is there a distributor cap on those things? If the ignition module is only $25.00 or so, you could try that too.

 

[Zenmervolt]

I've only ever driven 4-cylinder cars, and I have no idea what this "4-cylinder shake" that you peak of is. If the engine does not shake on other occasions, I would look into the fuel delivery system or the spark system, it sounds to me as though the engine is misfiring on at least one cylinder at low RPMs, which may mean that the idle is set too low or too lean. This would only become apparent after the car was warmed up because the choke (or choke emulation if it's FI) would compensate for the incorrect setting when cold because it would be delivering extra fuel. There are a number of possibilities here. Oh, just though of this as I was typing, if the car stalls out every now and again, you may want to check the fuel pump relay, at the age of your car, the relay is a definite possability.

Zenmervolt

 

[Pepsi90919]

Make sure the torque converter clutch is disengaging.

 

[Thegonagle]

<< Make sure the torque converter clutch is disengaging. >>


If that's the problem, which it could very well be, given your description of the symptoms, it will get worse. It will stall out on you, and eventually, you won't be able to get going again for several minutes. It's a fairly cheap repair, worth the $$ if the car is otherwise still fairly dependable.

 

[Nutz75]

it means you need a tune up and oil change, and a wheel alignment

 

[BDawg]

<< I've only ever driven 4-cylinder cars, and I have no idea what this "4-cylinder shake" that you peak of is. >>



A lot of people notice that 4 cylinder engines tend to shake. You can feel it in the break peddle, and the gear shift. I don't know why they do it, but you really don't notice the same kind of shake in 6 or 8 cylinder vehicles.

Do a google search on "4 cylinder" vibration .

Edit: Speeling error

 

[Sluggo]

<<

<< I've only ever driven 4-cylinder cars, and I have no idea what this "4-cylinder shake" that you peak of is. >>



A lot of people notice that 4 cylinder engines tend to shake. You can feel it in the break peddle, and the gear shift. I don't know why they do it, but you really don't notice the same kind of shake in 6 or 8 cylinder vehicles.

Do a google search on "4 cylinder" vibration .

Edit: Speeling error >>


In-line 4 bangers dont have the inherent balancing of a V-* motor ( opposing forces.) The more expensive ( or more dedicated to quality) manufacturers will put a nice counter balancing system in the motor. I think they all have a balancing system of some sort, but you can tell a difference in a BMW 4 banger than a Yugo 4 banger.

 

[BDawg]

I just had a thought. My wife's car used to shake some after driving high speeds. We had to turn the brake rotors in her car. I'm not exactly sure what turning the rotors does, I would think if there's a bad part, it would still be bad. But whatever it did, all the braking problems are gone.

When she would brake, she could feel the brake pedal and steering wheel shake. Are you experiencing that?

 

[Sepen]

Just put a Hemi in there, then you will see some shaking. J/K......

 

[LethalWolfe]

<< I just had a thought. My wife's car used to shake some after driving high speeds. We had to turn the brake rotors in her car. I'm not exactly sure what turning the rotors does, I would think if there's a bad part, it would still be bad. But whatever it did, all the braking problems are gone.

When she would brake, she could feel the brake pedal and steering wheel shake. Are you experiencing that? >>



When you press the break pedal on a car with disk breaks (like your wife has) the calipers (basically clamps) "grab" the rotors (basically disks that the tires are "attached" to) and thats what slows the car down. Thru normal wear and tear the rotors can wear unevenly causing vibration when you hit the breaks. You can machine ("turn") the rotors and that will give the rotor a flat, even surface again. Depending on driving habbits, environment, and type of car, rotors can be "turned' a number of times before they become too thin, and need to be replaced.

Lethal