First, some history.

A couple of days ago I went mudding. I have the Downey exhuast kit. I had not welded it together since it diddn't fit perfectly, so was only connected using the clamps that come with the kit. Anyways, I was bouncing around and whatnot and the 2 pipes that go into the Y-pipe popped out. I guess one of the rubber exhaust hangers popped off the mount and the exhaust began bouncing arond, hence the Y-pipe seperation. I put them back together, but have a really nasty exhaust leak from the front of the Y-pipe.

I have gone through all the electrical stuff, wires, cap, rotor, tps, afm,....
They all check out. The car runs fine except when at a stop, The car will idle at 800-850 rpms, then slowly/incrementaly drop. 750,700,650,600 ......all the way until the engine just begins to stall then it jumps back up to the golden 800 rpm. It will keep doing this over and over. I believe I don't have any vacum leaks. I haven't been able to find any.

Does the exhuast leak and probable lack of gas blowing by the O2 sensors trip the computer out? I have 2 sensors. I have not checked them yet, but everything was fine until the exhaust came apart. With the incremental rpm drop, it seems as if the ecu is making some kind of adjustment to fuel delivery. There are no codes. Is the ecu leaning out the fuel? The gas milage has gone to crap as well, maybe 100-110 miles a tank.

Sorry about the long post guys.
Thanks.

 

Greetings,
If you didn't have an exh. leak I'd go w/the tps outta spec but since you have an exh. leak, whalla! Fix that leak! The O2 sensors aren't getting a true reading and under/over compensating for that leak! Even though you don't have a code the computer is still compensating for that leak!
So, FIX THAT LEAK!

Good Luck Man!
Harry

 

I had the same problem when I installed my Downey "perfect fit" system several years ago on my old '90 4runner. I took it to a muffler shop and they laughed at how much money I spent on it and fixed the leaks for about $50 bucks. Actually, they welded the whole damn thing together at every joint. It's fine now; I've stopped making purchases with Downey since then. Good luck man.

 

Yeah, I was not very impressed with the downey system. I like the muffler and cat, but the pipes left alot to be desired. I don't know if I should just weld the pipes as is, or have a shop re-route the passenger side pipe behind the tranny. I forgot who did this but it looked really clean, plus the passenger pipe crossing in front of and lower than the tranny support would be nice.

Did your kit come with galvanized and stainless pipes like mine? That might be an for the welding portion....if I only had a mandrel pipe bender ...sigh

 

I had the same idle isue way back when and it ended up beeing a worn throtle body. I would be imagine that exost leak could be the cause of your problems. Your computer is confused for one reason or another.

 

I sure wish that I'd seen this thread before I bought this crappy Downey Exhaust system. My idle keeps dropping from 800 down to almost stalling and back up. Really think that it's an exhaust leak thing? If anything my truck used to idle too high before this. Not anymore. This thing is becoming a freakin' money pit! Got oil on my cluth plates. Trying to figure out where it's coming from. I perish the thought of it being my rear main.