1999 Prix Shakes Help Me Please

[davea21]

First Time posting.... long time reader.

I have a '99 Prix that overheated on Jan. 15th. My brother replaced the water pump and cleaned the radiator. While there, he replaced the drive belt, too. We then noticed the car leaked coolant on the opposite side of the water pump. (Around the Thermostat) We replaced that too and had to resort to replacing the lower intake gasket and upper intake gasket. After all that was done, the car shaked a lot. He made some adjustments and car shaked less. It's been 2 months and I still don't have my car! Last week one mechanic said it was the heads that needed to be rectified. Did that! Car still shakes. Replaced one Fuel Injector. Still shakes. This morning my brother called and said that he had cleaned the injectors with some Acetone treatment. But the car still shakes.

I've driven the car several times. It shakes the first time you start it. Not as you drive. Shakes on idle (feeling like it's gonna turn off but doesn't). I notice my RPM's are high when driving. I've almost had it with the car. Prior to it heating up and opening and removing the intake cover, the car did not shake at all. I drove it off the car dolly when I got it home. (I had been stranded).

Questions: What can it be? What can I do? Did I really need the head job? (That mechanic said that Injectors don't get cleaned, they get replaced and that I should do that) course each injector costs $115. I can't believe three can be messed up... seems like too many. Please Help! Thanks, Dave

[JJUBECK]

Could be motor mounts. Cheaper then getting your heads done.
Pop your hood have someone get into your car and slowly run through each gear. Watch to see how far your motor jumps when you shift from neutral to drive and neutral to reverse. If your motor moves a whole lot then that would be my bet.

[spinktec]

This may be a little obvious but; what RPM is it idling at? Can you raise the RPM a little with accelerator pedal and make it stop? If so does the idle go up when you turn the steering wheel or turn on the air conditioning? I ask becuse you say it doesn't shake when the car is moving down the road.

[Flatrater]

To be honest with you I suspect the repair to your head is the cause to your problem.

What kind of adjustments did he make? Becuase there really isn't any adjustments possible on this engine. Any anything you adjust the computer will try to compensate for it.

Is the check engine light on?

[JoeJoe231455]

Which engine is this?

When you overheated, what temps were reached, and did you keep driving it until it gave up?

[davea21]

The car began shaking before the head the job. One mechanic said that the head job needed to be done because the car overheated. The light comes on and off. Not too sure what the RPMs were when I was running the car, right before the head job, but I think it was near the 3000 mark at 65 mph. The car did overheat and I was trying to reach a service station. The TEMP light lit up and then the car stopped on its own.

Waited about 30 minutes and then drove it to the gas station about 2 blocks away. I didn't feel any hesitation, shaking, or problems when I drove it up the tow dolly, nor off the dolly at my parent's house.

[mfastert]

just wondering what was wrong and how you fixed it? I'm having the same problem.

[kilroypr]

Well man to be honest, did you checked the damper?
Have you ever changed the damper? When the rubber coupling brakes or wear out the engine might vibrate a little on idle and be less perceptible as engine speeds up.
What they did to the heads? Flatrater is correct. These engines are not adjustable and if you change anything the PCM will try to compesate for it

[GTPCatz]

Check Misfires....
Get a Presure check on each cylinder....
It could be a cracked Head/Piston

But then again that should throw a code....
I would also check engine mounts....upper and lower

[kilroypr]

If I read correctly the problem originally was that the car was leaking water at the pump. They replaced pump and gaskets and after that then the shaking started. I do not see how changing a water pump gasket could make a cylinder pressure to change

[GTPCatz]

no but if the car heated up to extreme temps breakdown of the cylinder walls can occur....

[GTPCatz]

also If I read the question right...they have no idea what could be causing this...

Massive Vibration is usally related to Cylinder/Head Problems....anything from a Bad Misfire to a Broken Piston

assumeing the motor mounts are in working order

[kilroypr]

Well I have had broken pistons and no vibration what so ever and the debri was still on the cylinder. The engine that I am replacing now. Excesive heat yes could break a cyl wall or break a piston but the car would be missing a lot with SES or hessitation due to the lost compression on the piston. I bet the pistons and cyls are ok

[GTPCatz]

betting and knowing are 2 completely differant things...

I am just throwing out Suggestions and things to check....I would almost put my money on the Motor mounts though....like I said since your not getting a SES light.

[kilroypr]

Correct, no SES light no Cyl or Mis related issue.

What I have seen when mounts are broken is engine excesive movement when shifting gears but besides that and if the engine is ok no excesive vibration. If the mounts are gone and when replaced the engine stil vibes then this vibe could have contributed to braking the mounts.