how long can i drive my 2007 pontiac grand prix with a bad valve?
the car drives fine while driving ,but when i stop at a light or any time it shakes like a miss
in the motor.i took it to a repair shop and had plugs and a coil put on it,but the mechanic
found out in the process i had a bad valve
Fix it as soon as possible, postponing repairs like this may end in serious damage to your engine. If the valve breaks it can drop into the cylinder and kill both a piston, the cylinder head and the cylinder bore and potentially cause damage to the crankshaft.
If you want to count on buying a NEW engine, drive it as long as you can...don't take it on the freeway or any other place where you cannot immediately pull over...I'm with Lars on this one DO it RIGHT...or not at all ('course there's always a question of being able to afford a loaf of bread and some cheese vs. installments on your mechanic bill)~
It's NOT a matter of how long you CAN drive it. Stop driving it ASAP, get it repaired before you have to replace the entire engine or worse....
If you truly had a bad valve you'd have a "dead" miss. That is to say it would miss all the time. Not just at idle. With your OBD II vehicle your "check engine" light would be on and a misfire code would set. Get a second opinion. Have a compression test done. A cylinder with a bad valve, that's not firing will read very low or zero on the compression test. HTH. -Jim
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