97 mazda protege shake on drive mode


#1

this mazda is relatively quiet when on park and neutral and can feel more shake (feel from steering) while shifting to drive mode while idle/before redlight. it can feel more shake while on speed over 70 mph. it feel ok on speed lower than 70 mph.

just wonder if the engine/trans mount is the root cause. the trans is on drive side and engine is on passenger side. engine inside mount has been replaced and doe snot help much.

thx


#2

@shiguiy
Try And Download A Copy Of A Mazda TSB (Technical Service Bulletin) #B006/98, Written To Help Technicians Diagnose Excessive Vibrations In 95-98 Protégé Models With Z5 BP Engines And Automatic Transmissions When In Drive Or Reverse Gears.

Apparently, Mazda feels that the #1 engine mount (driver side, upper?) material can become too hard and or crack. It seems they had to issue an improved mount to remedy customer complaints.

I’m not saying that this is your specific problem, but certainly worth consideration.
CSA


#3

thanks. the drive side is the trans and looks like there is only one mount is there for trans.

I notice that the front mount moves when I shift on idle. I will try to replace that one first.

thx


#4

Ok in neutral but shaking at idle in Drive isn’t an uncommon problem, and there are numerous possibilities. The engine has considerable more load in Drive vs neutral, even at idle rpm. So anything slightly wrong with the fuel/air mixture, misfires, etc will show up in spades and can cause engine shaking. One reason it could go away at higher than idle rpms in Drive is if the mixture was lean or injectors uneven at idle. As gasoline needs increase, small problems in mixture or cylinder balance symptoms will be swamped by the amount of gasoline injected. An analogy, if your garden hose-end sprayer is a little clogged up, that will show up more when adjusting it to spray very little water, like if you want to water a delicate plant. If you turn it to “full on” it will spray just fine.

One area to look then is too much air at idle due to vacuum leaks, too little gas due to clogged injectors, or injector to injector imbalance.