1987 Century with Issues..

Hi guys, this is my first time posting to a list other than the chevy one.

I have a 1987 century with some problems. It began acting strangely (vibrating when you accelerated, and no power) about a month ago. My mechanic told me it had a bad ignition coil so I checked it and replaced it. It was the first one on the left (1&4 I think?) Now that operates correctly, but it has developed other problems. When you start the engine the rpms drop a long way, almost to the point of stalling then immediately rev back up. The car also immediately stalls when you put it in reverse. Any ideas?

I've also been told the alternator had bad diodes and needs to be replaced. My other car did similar weird reving things when it's alternator bit the dust. I've also checked the spark plugs, a few are badly corroded but still seem to work. I'm replacing them and the wires tomorrow. One more interesting tidbit. The car had a problem stalling out before, so the previous owner (mother in law) took it to her mechanic who she says "disconected something." I've no clue what, except that there is a plug which plugs into a socket on the lower part of the engine/transmission on the right (facing the front of the car) near the axle. There is an obvious sensor located there as well. The connector has four prongs. I have no idea what this is.

Sorry for such a weird car! We're trying to decide to keep it or not. Good gas mileage and a small car with a big car ride on the plus, wierd stuff on the minus. Only 70k though!

Thanks for the help! -Ben

Go ahead with the tune up first, then clean the throtlebody. Hopefully it will run better. The thing that was unplugged is your transmission lockup solenoid. If it's a three speed vehicle, just let it be. By disconnecting it all the vehicle does is consume more gas. However, if it is a 4 speed transmission, the solenoid should be replaced. The solenoid was probably causing a stall situation.
GOOD LUCK.

I agree that the unplugged plug is the tranny connector - contains 1st, 2nd, hi gear switches and TCC. If its a 4spd tranny then you MUST get this fixed or the tranny will fry itself

idle problems on those - is it the 3.3? look at the 4 way vacuum connector on top of the intake - they leak BAD. tap the maf with a rubber mallet while idling - stumble = bad maf.

check TPS voltage and throttle angle with a scan tool (.5v at idle - 0-1* angle