Hello all,

I just thought that I would get your collective input in how to proceed.

Some background on the car. It sat for years with a fuel pump that was out and a transmission that was shot. Some money became available allowing me to fix it. It being 17 years old and having sat for some time has created some work for me.

After getting the new pump and the transmission fixed, I began driving a little at a time. About 100 miles before it threw its first code, P0171. So I start to look around under the hood and find a lot of rotted/cracked hoses. A stuck shut PVC and I notice the throttle body plate gasket sticking out on all sides. So I fix all of that, "rebuild" the throttle body (it had been sucking oil into the top of the TB) and clean the MAF sensor. Get it all back together and it appears to run fine.

I drive it to work and all is good until I leave work and it wont start. After about five minutes I get it to start by putting it into "clear flood" mode. I make it home with no issues. I get home and do some more troubleshooting and find that the vacuum hose from the fuel pressure regulator smells like gas and has was looks like weeping gas dried on the outside of it. Because of this, I replace the fuel pressure regulator.

After that I start it up and it runs great! Take it for a test drive, both spirited and normal, and all is good. I get home park it on the driveway and go in for a little bit. A few hours later I go back out and it starts but run REALLY rough. Throws a flashing "Service Engine Soon" light. I quickly turn it off and a few minutes later start it again. It still idles very rough but the SES isn't flashing. I grab the code scanner and shows a P0300.

I go out today and from a cold start, runs and drives great again. In conclusion it appears that after a drive of any length it is hard to start and sets off the P0300 code. Heat soak of some kind?

Things fixed/replaced:
Fuel Pump
Fuel Filter
Fuel Pressure Regulator
Air Filter
PVC Valve and assorted vacuum hoses
Throttlebody cleaned / new gaskets
Cleaned MAF

On order:
New front o2's
New plugs and wires

Any ideas?

 

Ive never had this problem but ive heard of ICM getting heatsoaked and causing issues. I dont know if it would run rough or just die altogether. Goodluck.

 

Thanks Chris. I'm thinking the same thing. That or the coil. I am researching how to test those now. If its possible. So as to not throw money away if its not needed.

 

Check on Youtube, Scotty Kilmer. Pretty funny dude but gives you easy troubleshooting skills for codes... Might help, I had the same issues and ended up being corroded battery cables. Check all your grounds and actually get a flashlight and look at the ends real good for rust and oil build up, also check the ground wires coming off your ICM at the coil. Our cars are SUPER sensitive to having bad grounds.

 

http://shbox.com/1/4th_gen_tech2.html#opti_test
http://www.mainstreamtopics.com/foru...rt-diagnostic/

you might be able to use some aspects of these diagnostics to help you your search. good luck with fixing