Ok, Did timing belt replacement, engine coolant temp sensor & O2 sensors all at the same time. Now have a problem. when cold start, runs fine. once it starts to warm up it starts to miss/bog when giving it gas somewhat hard. also under load/30mph in overdrive and give it gas. after doing some research here i tried just about everything. AFM test, coil test, jumped fuel pressure, even installed old parts. still have problem. but when I disconnect the AFM/MAF the problem goes away. It does have pinging at throttle and idles kind of weird now but missing/bogging gone, HELP out of ideas. Car ran great before this. 1993 Lexus LS400
What happens if I leave the AFM/MAF unplugged?

 

It will run VERY VERY rich. Your MPG will go WAY down, I get about 13MPG. I barely drive it lately anyway. My AFM has been unplugged for a while now. I had the exact same symptoms as yours except I had the pinging before it was unplugged. You say you tested the AFM? I know if it's bad sometimes it doesn't throw a code. I only got a code when I unplugged it. This thread might help you. https://www.clublexus.com/forums/ls4...nging-too.html