Check engine and Temp light flash, then the crazy stuff begins

[yunkeraj99]

Ok, well I first want to start off with saying that I have been all over this forum for weeks now to no avail so I though what the heck and I would post to some of the others with the same car. I have a 1990 Buick Century V6 3.3 that has about 145,000. The car runs great except when it wants to pull it's deal with with the check engine light and then the temp light coming on and the they start flashing. Here is the deal, I had the codes read from a friend that has a nice code reader, all it would come back with is TPS High, can't remember the exact number. So, I replaced the TPS thinking that was it. Hummm.... well no! This can happen at any time mind you, start the car and it will run fine then the lights show up like the grizwald family Christmas and the car revs up and then starts to cut out. Almost like it is flooded. You can sometimes restart the car but most of the time you have to have the gas all the way down, it will start and rev up then cut out. I have a manual gauge and the temp never gets near the red and also this can happen just when starting the car. Now to what I have pulled sensor wise. I have disconnected the MAF and no change, the Idle air and no change, all AC sensors (not that it works) and no change. No vacuum leaks at all. Can pull vacuum from TB and it will rev up but will not stop the stall. Disconnected the battery for 1 hour and that did nothing. Sometimes I can drive for a hour and have no issue and then others it will happen the first time I crank it. I am at a loss. Have talked to the auto part store for some time and we though that it may be a temp sending unit, nope. Ignition coils, but not like it is happening. It will rev up and down for no reason before it cuts out and TPS is not moving. ECU??? That is what I am thinking!!! Let me know what you think. Thanks in advance!!

[djirene4206]

Have you checked the ECM harness ground? And what about the temperature sensor relay? Check the grounds coming from that; Had same issue with my car when first got it. GM did a poor wiring job on the Buicks! If that doesn't work, you can get a used ECM for about $50. Finally the reason there is no change when you unplug other things is your ECM is already running in 'default' mode.

[masterman6977]

hey dont feel bad mine runs great but when the check engine light comes on my speedodmter cuts out one day it work and the next day the check engine light comes on and there goes the speedodmter and been every where trying to find out what is causeing it but no luck anyone got any ideals what might be causeing this

[yunkeraj99]

Ok, I changed the ECU and all is well now!!! Thanks for all your help with finding the cause of this issue.

- Aaron