Im new to the boards, im trying to figure out why my parents car is shaking when its either in park mode, or at a stop light or any gear without pressing on the gas. Its a 1995 Mazda 626 4 cylinders automatic, we have so far replaced the spark plugs, spark plug wires, and filter and cleaned theMAF or AFM?The engine has around 99,000 miles. If i give it some gas, the motor will idle fine but the rpm will sit around 2000, and it'l drop back down immediately with the same problem. IT feels like the engine wnts to stall or shut off. Please help me solve this problem. The shop wanted to diagnose it for $50, then they'll tell me my problem. Any help is greatly appreciated. thanks for your time
BTW, There is no engine check light, but it came on for a few seconds then went back off.

 

take it to an autozone and have the code pulled 1st then go from there

 

check oil !?!? Maybe dirty injectors....

 

nah, that doesnt sound like an oil thing. are you sure it isnt any of the mounts? make sure the engine mounts and the tranny mounts are good.does it feel sluggish when it's driving? if it does, check the fuel system...run some sort of fuel additive...honestly it could be a lot of things, but without more information, diagnosis could be tough. if you know anything else about it....it would be helpful. btw, is the check engine light on? if it isnt, then running the codes isnt going to help.

 

If the CEL came on even for a short time then code may have been stored. Only way to know is to codes checked and see what come up. If code is set then may be a missifire that may guide you to a cylinder or something else altogether. Good first step in this case would to be get a code check though. Do you need to keep throttle pressed to have an idle speed of 2000 or will the engine do this by itself without your intervention.

 

whoa, so many responses. this is a great board !

6man: I went to Autozone, it seemed like the workers there didn't know what they were doing. Could i check the codes myself? I kind of forget how to do this, i remember it's something with the ECU, i'll try a search on the board for that but thanks for the help!

dave87: I just changed the oil about 2 weeks ago, i Checked the oil, but i dont think it can be an oil problem. but thanks

woo7: I can see that one of the engine mounts ( on the passenger side) is about to get busted anytime soon, but 1 mount can make the idle to drop rapidly? when im driving it, it feels normal, Check Engine Light is off..is there a way i could get the code if its off? i have an OBDII machine to run codes, but i dont think it'll work on this model ( the machine says its only for 96+ models and up)

babyhuey: IS there a harness i can plug a obd1 scanner up to? i tried searching under neath the dash and around the drivers' side, i know on my nissan, the harness to plug in the diagnostic machine is underneath the dash by the fuse box, i see a DIAGNOSIS tab in the engine bay. What is that for? Sometimes at start up, the idle speed is 2000, then it'll drop down and wants to shut off. If i give it a good kick of gas, it'll rise back up to 2000 or higher then drop back down. Also, when i put the gear in Neutral it will rise.

I gave it some fuel system cleaner, that didn't solve the problem. What is weird is this problem occurs every other day. Today was a good day. I dont know what else i can say about the problem, Driving on the freeway is fine no hesitation with the gas or anything...It only happens when i come to a stop light. Maybe im going to search around on the board to find out how to find the codes. Thanks alot for your help i really appreciate your time!

 

Hi,
I just want to know if you have any luck on this because I have exactly the same problem. The car has 144K miles but still runs great especailly after I cleaned the throttle body and the IAC. I replaced the gasket as well and set the idle at 700 rpm and set the timing too. I would greatly appreciate if you could tell me if it has been fixed and how it was fixed.