Ok here goes...90 GMC S15 6 cyl 4.3, fuel injected.
last week all of a sudden my exhaust manifolds have started to run very hot and at night you can see a red glow.
I am in Toronto Ontario Canada, do not have a good mechanic and have been to many shops and $1700cdn later this probem is still not solved.
Truck for the most part runs and drives as usual....and I only found out about the manifold problem when I was hunting for this burning smell that started all of a sudden and sure enough a night test drive confirmed the manifold was glowing.
Since last Thursday I have been to several shops and each one has claimed to have fixed the problem and here is what has been done:
new map sensor, wires, plugs, cap, rotor, complete new exhaust, the problem still continues.
I talked one shop into putting it on the scanner and the mechanic said I should replace the engine because it would take too long and cost too much to diagnose the red hot manifold condition, but I did manage to take a peek at the scanner when it was hooked up and saw the o2 sensor switching from lean to rich and back but staying on lean longer and it wasn't switching that fast.
I am concerned because of the fire hazard and that it the heat is caused by it running too lean then I have probably already damaged pistons.
The truck is not using more gas so I fear it is in fact running lean.
one person did suggest a fuel pressure regulator but I am looking for more ideas from any mechanics here.
Shops these days only want to swipe my gold visa card...not fix the problem....$1700 in 7 days and counting and the problem is still not fixed.
any help from mechanics would be appreciated.
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