I have a 2002 RX300 with 127k miles. A year ago, I replaced the breaks, struts, control arms, sway bar links, VVT solenoids, fuel injectors, spark plugs, coil packs and knock sensors. My MPG has been in the high 19s around town. This forum is great!
Everything was until this week: I was driving when the p0303, 0304, 0305 and 0172 codes came on with the obvious loss of power and MPG. Additionally an odd noise when the engine is under load. It can best be described as a "pesh pesh" sound similar to an air pressure relief valve opening.
I replaced all the coil packs and the MAF then cleared the codes.
I took the car for a short test drive. It starts, idles and drives with a light load without a problem. If the engine is under load (like accelerating to merge onto the freeway) the "pesh" sound comes back. I have looked at the engine and exhaust but cannot see anything obvious as the sun was setting.

Any ideas as to where this sound could be coming from? Maybe a hose, worm hole or excessive dark mater.

Thanks for any suggestions.

 

Hello,

The list of parts you described will cost a fortune to replace, for injectors, even some questionable aftermarket options go as high as a $100 a piece, and about $60 for each coil. Where did you get all the parts, and what was the reason to replace all of them during the first repair?

Places like eBay and Amazon carry a ton of counterfeit junk, it is very easy to get burned by it. If you still have all the parts you took out of the car, I would suggest putting them back in to see if that will make any difference. If not, however, best bet would be to find a low mileage used OEM parts instead of getting everything new, otherwise it will make for a very expensive repair.

Hope this helps and best of luck!