i have 2.0 engine in my cimarron. i give it tune ups & change oil every 5000 miles. for some reason when i am at a stop light and my foot is on the break. the oil pressure drops and the car begins to shake. when i put the car in nutral and let off the break the shaking stops but the oil pressure remains the same. i dont know if it is a bad mount or a bad oil pump. my local mechanice are really stupid & the dealer is a rip off. so can someone help. AND DOES ANYONE ELSE HAVE THIS WEIRD PROBLEM...MY CAR DOESNT COAST & INSTEAD IT SLOWLY SLOWS DOWN. IT HAS BEEN DOING THIS FOR EVER & NO ONE CAN FIGURE OUT WHY. THE GM DEALER SAID IT HAS A TIGHT TRANSMISSION AND ITS A GOOD THING BUT IM NOT SURE. THE CAR DRIVES AND SHIFTS LIKE NEW. ITS JUST WEIRD.
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First try removing the egr valve's vacumm line! It should be the same location as mine and is behind the valve cover close to the distributor.It is about the size of a tennis ball.If the problem goes away that is the problem.However after reading the specs on your page about the car I see it is a automatic.That tells me right off the TCC or better know name torque convertor clutch(solenoid switch) is probably causing the problem based on the symptoms.Normal problems from this are cutting off in reverse or when coming to a stop.However a easy way to check this is by disconnecting the switch plug on the transmission.I have no idea where I own a manual 4spd.And if the switch once disconnected clears up the shake,the switch can be replaced and definitely change the filter and fluid in the transmission because what happens is the fluid breaksdown and no longer reduces the heat which inturn burns up the switch.You can drive with it unhooked and may reduce mpg thats all.Advance auto,napa sell that part.Maybe some of the other slackers on here with autos can tell you where that tcc switch is so u can unhook it and verify that could be the culprit and not the egr(I suspect the TCC).OK
Ron... two very good things to check ! "Normally" when the TCC switch goes bad it causes the engine to stall , as like trying to stop without depressing the clutch pedal. The convertor is locked up, with the TCC engaged... just like when the clutch is engaged, and only shifting into neutral will keep it from stalling. Puting vehicle into gear after that will cause a stalling condition or a feeling that someone has banged into the cars rear bumper at about 25mph. It really engages with a BANG ! The harness/plug is usually located where the transaxle bolts to the engine. Not hard to find, as it's the only wiring that enters the transaxle/transmission. He didn't mention the stalling part, so i'd look in other areas.
EGR will cause shaking and stalling, depending on how bad or carboned up the pintle seat has become. carbon will hold the EGR in the open position. Test, as you stated is easy, unplug small vacuum line to EGR and restart to see if problem goes away.
Another area, and the most logical would be a cracked or broken vacuum line underhood. Take a can of carb spray and squirt around the hoses.... if idles smooths out or speeds up, you have a leak and hose must be replaced. Least expensive cure of the three. Take the spraying slowly as just going crazy spraying doesn't tell you the exact area the problem lies in.
Hope this helps, good luck with the Caddy !
Alan
Also take a good look at the upper trans mount. When that goes bad, it normally causes a bad shake when stopped with foot on the brake.
