I need help…for real. I have an 08 Is 250 with a little over 200k miles. I’ve had it for about 3 years and have had a check engine light for about a year of that time. I took it to a mech when the light first came on because it was misfiring so bad I couldn’t even drive. They did a horrible job, diagnosed it as a bad ignition coil d and replaced it, but the light never went away. I have been able to drive it since then but recently decided to try and get it fixed again. I took it to a Toyota tech and he said the MAF sensor needed to be changed, so I changed it myself, and at the time I didn’t have misfire codes I only had P0171 and P0174 system to lean bank 1 & 2 codes. Replacing the MAF sensor with an OEM one removed those codes but now I have these three codes (p0352,354,536) cutting on and off with relatively aggressive misfires. I have yet to pull these coils mainly because of the giant intake manifold that sits directly on top of them, but just need to know if anyone has seen anything like this. Do I simply need a complete tune up (plugs and coils)? Could there be a shorted wire somewhere? Any advise helps!

 

A common test would be to swap coil packs from B1 to B2. See if B2 issues move to B1. 200k, when did it have plugs last?

I'd start w new Denso plugs from trusted source. Check gap, pull the manifold and install plugs an swap COPs. Obviously look for wire damage and gently pull on each wire of each connector on B2 to make sure none pull out.

Do you have a DMM?