Diagnostic Code 45 on '91 Blazer 4.3
 

Code 45 is "rich exhaust indication" according to my manual. I replaced the 02 censor a year or two back with a Bosch brand and have driven the vehicle modestly since then. It spitts and sputters every now and then, the service engine light comes on and the spitting/sputtering goes away for a while but returns after 20-50 miles. What's going on? :confused: Any input is much appreciated. Another member was having the same problem but he hasn't posted for a while. I'll try and dig that one up for others to view. Thanks.

i had a similar issue though it didnt trip that code and i was due to my own stupidity, when i replaced the motor in my '94 4.3 i forgot to tighten down the distributor cap and the timing was all ****ed up. not sure if thats of any help to you but who knows if your cap might have rattled loose and your timing could be off

No, it's not the distributor, it runs too good most of the time and I double check it today, thanks for your input though. I believe it has something to do with the emissions, or at least something along those lines.