I recently came across this thread due to my 1998 626 having a rough idle after getting it back from the shop. Around November 2018 (Thanksgiving) my fuel pump went. I went to a junk yard with a buddy of mine and got a fuel pump from a junked car and put in into my car. We didn't drop the tank instead we cut a hole in the floor board under the backseat and replaced the part. When trying to start the car after replacing the fuel pump the car still would not start. The engine would spin as if it were going to start, but nothing... My friend who is a mechanic checked to see if the car was getting spark and fuel which it was, but the car still would not start. Just in case I bought a set of new spark plugs and installed them, but the car still would not start. We tried using starter fluid, but the car still would not turn over. Finally I had enough for that day and as it was the holidays I decided to just leave it and come back to the car later.
While the car was sitting my friend contacted me and said to check the crank shaft positioning sensor and see if it were dirty. I checked it and although it had some dirt/ old oil on it it was fairly clean, but I decided to go ahead and replace it anyway. Still no start.
Fast forward to last week. I had the car towed to a repair shop where they found that the timing was off and they corrected this issue and now the car starts and runs, but with a very rough idle especially on cold starts. There is not a check engine light on the dashboard. The guys at the repair shop suggested I take the car to a transmission repair shop due to the car jerking really hard when I put the car into drive. The guy at the repair shop adjusted the idle lower to prevent some of the jerking. When I am driving the car acceleration is hit or miss. Sometimes it accelerates normally and other times when I push the gas I get nothing, but a high rpm and a slowly accelerating car. At red lights the car shakes, jerks, and sometimes stalls due to the idle issue. Luckily I live in New Orleans which is flat so I don't have to worry about going up hills and can avoid most bridges.
If anyone has suggestions on what I can do to resolve this issue that would be great. Of course ideally I would like to find a Mazda expert here in the city, but thought I would check here first.
Thanks in advance for your help.
I have an interesting electrical issue with my '98 Mazda 626. The car starts and runs fine except if either the AC or the headlamps are on. If either is on, the dashboard stops working and the car does not shift properly.....any ideas?
Just came across this thread. I don't think a 98-99 key would work. Here's an OEM Mazda key showing to be compatible with 2000-2002 models for your reference https://www.mazdapartsprime.com/oem/mazda-key-bjyv762gx.html . Hope this helps.
Finding an S2 hardtop boot lid in good nick, is super difficult. They all rust along the lip - for some reason. I saw your post on RX626.
I have a spare one, but it's only in poor to fair condition - it has rust also.