hi,1993 delsolb7 w/ a d15b7 eng.was throwing code 43 & 1. I changed out fuel f and code 1 is now gone but 43 still hanging out and only comes up when driving @high rpm it does'nt over heat but engine sometimes feels hot.whats up ????????????

 

Three primary causes: failing O2 sensor, clogged fuel filter, and failed/aftermarket fuel pressure regulator. You said you replaced the fuel filter, so we can rule that out. Test your fuel pressure regulator, or just get one from a junk yard - they're stupidly cheap. There's a proper way to test your O2 sensor and wiring, but you'll need a voltmeter. RonJ should be able to post the how-to for testing it. I don't remember the process or numbers off the top of my head.

 

thanks 4 your reply I was also able to bleed air out of the radiator as well, have read that its also tied to idle.I will able to switch out a fpr 2morrow hopefully that will do it. Took it out 4 a ride no cel but still choppy idle, maybe tomorrow 4 fpr. cel usually does not come on till later

 

I've had code 43 come on twice now just because of faulty o2 sensors. sounds like you are running extremely rich or lean. Both will cause choppy idle and both will cause code 43. When the code is thrown the ecu adds or removes up to 20% fuel to correct your a/f. Can be permanent if not corrected. Time to replace your o2 sensor in your catalytic converter.

 

If the CEL isn't coming on until your car warms up, and the problems aren't starting until the car warms up, I'd lean towards blaming the O2 sensor as well. You should still test the wiring before replacing it, though.

Paging Dr. RonJ and/or HPH for flowcharts!

 

Could also be a hairline crack in the exhaust manifold right next to the O2 sensor location. Causes the cel code 43 (messes up the reading).
Before you spend $80 for the sensor take off the exhaust manifold heat shield and look for a crack. Common problem. Cheap ebay header is a good replacement option $60.