If the ERG valve is stuck and/or the ports clogged, remeding these maladies may solve the problem. However, after you clean everything up, check out the ERG for operation. If does not operate, it may have failed or there is a problem in the control feeds to the valve. Recirculating exhaust gas back into the intake mixture lowers the combustion temperature, hence reduces NOX. Sadly, it also reduces efficiency a bit.

Well the facts are in, my "trusted" auto mechanic's hands are dirty. As mentioned he priced a complex exaust part for a 1990 Mits Galant at $270, wow! He of course charges an hourly rate for his work: $65, less than the dealer charges, but still a "living" wage and sufficient to pay overhead costs at the same time. I always supposed he also marked up the cost of parts, maybe 10 to 20 percent, and much of that was due to the fact that he can purchase at a discount compared to what I pay. Well as mention above I found the needed parts and they came with delivery at a price of $130. So, today while at the one of the auto parts houses he priced parts at I asked after the price of the parts, $170, even to me, and that's $100 less than the mechanic wants to charge me. I'd be willing to bet he gets the parts for closer to the $130 line. In any case I get this picture: Time 1 Hour: cost $65, Parts mark-up $100, true cost per hour: $165, plus tax. I'll work on this one myself and may look for another mechanic, but my hopes of finding a more honest one are not high.

I think you should just try to pay the guy the entire amount if at all possible. He is being very nice by taking the lower bid and he will probably lose the use of his car for a few days while its in the shop being fixed. If he wanted to, he could probably ask you to cover the charge of a rental car for his use during this time. I would consider myself lucky that he isn't doing that and just pay him if you can.

I often use PartsDr.com RepairClinic.com AppliancePartsPros.com There are storefront sources who sell new items on eBay, judge per the longevity and seller ratings. There are many others. Google the part numbers of needed items for best prices if you're inclined to shop that way. I had a bad experience in June with PartsIPS.com (although ordered from them without incident them a year prior). Bought many times from SearsPartsDirect.com but has become unreliable. All sources may be affected by COVID for item availability.