An off brand muffler shop replaced the two dual tail pipe mufflers on my brother’s 1990 Nissan 300 ZX (26,200 miles) with two smaller, single tail pipe mufflers. About 2-3 miles after leaving the shop while in city traffic, I noticed the idle speed dropped down to 300-400 and about 1/2 mile after that I noticed smoke. I raised the hood to see a small fire and found that the exhaust gas sensor on the top, left, back side had melted and caused the vaccum hose to the fuel damper and another sheath to catch fire. Did not inspect the EGS on the right side. Thirty miles earlier, I had 4 fuel injectors replaced at the dealer with no apparent problems. So, did the use of the single tail pipe muffler cause the exhaust manifold to overheat and melt the elec connection? THANKS!!
Not knowing exactly what they did, I would believe it is more likely they did something that caused the fire other than the change in the exhaust system. About all the exhaust system can do is add a little more back pressure and that would generally show up as reduced power, not a fire. Bumping a fuel line and maybe causing a split that leaked, could cause the fire however.
Proving it could be very difficult.
Thanks for your response, I took the car to the dealer and they said the #5 ignition coil went bad. So it’s unrelated to what the muffler shop did or the FI work done previously. The EGS is on the bottom not top, the connection that melted was to the ignition coil.