Here is my problem. Every so often, maybe 3 times a week, My SES light will come on and my tach shudders for a moment. I can feel the car is lacking power. The SES light will shut off sparatically and the tach shudders again and the engine has full power. When the SES light is on it feels like something is clogged and the engine just cant perform right. Here's the funny part. If I shut my car off when the SES light is on and I restart it, it will stay on until what ever it is causing the problem fixes itself and it will go out. If I shut the car off with the SES light on and do a diagnostic check it only displays code 12. When I turn the key off and start the car again the SES light goes off and the car runs fine again. This problem is more annoying than anything else right now. I have had this problem about 2 months now. I know it is not anything clogged in the exhaust system because I just completed a header install, neew cat, and 3" pipe all the way back. I have good plugs, wires. I replaced the cap, rotor and coil about 6 months ago. Pcv valve is new. AIR pump works. What can be doing this? I appreciate any help.
Tony

 

With a problem like that I'd go around the engine and check every connection for any corrosion or loose connections.

You gotta remember the connectors are ~20 yrs old. Plastic deteriorates and becomes very brittle after a while, as well as any oxidation on the wire terminals themselves.

 

bump - any more thoughts?

 

That is really wierd you cannot get a code. I threw a SES light, and it went away on the next restart. I was able to pull what code it was without the light being on.

Do you know anyone with a scanner you could use while you drive?

 

Nope, I do not. It is odd because when the light is on my exhaust output is more, I have a small leak at my collector and when the light comes on the car kind of bogs a smal bit and the exhaust is 2x as loud at the leak. When the SES light goes off my exhaust leak is much quieter. I have been racking my head to figure this out, it makes no sense. I agree I need a way to diagnosis this while driving the car and pull the information about what is going on in the engine when it does this problem. There is a pretty good local mechanic down the road but I hate to shell out the ducks for his service to probally replace a dumb sensor.
Tony

 

i dont mean to be insulting, but do you know how to flash the codes. i only ask because for a long while after i had my car i was doing it wrong. its simple but being me, i still figured out how to screw it up. i would see the code 12 flash and i figured it was all good. i didnt know i had to wait for two more 12's then get the cde(s) followed by three 12's.

 

I don't take anything insulting wise. I can't even get it to flash code 12 anymore. It stays on constantly and when I jump the pins or even hook up my $20 code reader it will not make the SES light flash to give me a code. I am wondering if my computer is going fruity.

 

You could try disconnecting the battery (or ECM power) for about 20 minutes to allow everything to clear. If you disconnect the battery, you can drop the ECM and check the harness connectors while you're waiting out the 20 minute power off.

 

Took it to the shop and this is their professional diagnosis. The Computer is wacked out and needs replacing and my TPS needs to be replaced. It can all be done for the grand price of $780.00 LOL Not in this lifetime will I pay for this. I have found a replacement computer for $50 and the TPS is $25 at advance auto parts. Will buy computer tomorrow and have shipped in from California. Hope this fixes my problem. This explains why the computer would not give me the trouble code for the problem. Thanks for the help guys
Tony

 

awesome, im glad u got it figured it out.

 

I just read this for the first time & was leaning towards a faulty ECM. If you haven't bought it yet, try http://tacreationsusa.com/ I got my 305 TBI ECM for $30.

 

PH, Thanks - I bought it on Friday. Here's the weird thing now. When I got it back from the shop, the car has no problem at all. No SES light, no hesitation or anything. I looked at my carb and see the mechanic had removed the air cleaner and messed around the carb area, he made it a little more astetically pleasing to look at. I am wondering if he just fooled with the TPS connector a little. The computer will be here tomorrow so I think I am going to install it anyway to see if there are any differences and also replace the TPS as well. Thanks for all the advice guys.
Tony