22RE blows raspberries

[KidVermicious]

So, I'm kinda stumped here. I've got an exhaust leak (I think) that I can't find, and it's driving me nuts. Here's the thing - the motor sounds fine at idle. In fact, it sounds fine through the entire rpm range when the truck is in neutral or the clutch is in with no load on the engine. It even sounds fine on the freeway or cruising down the street at low RPM. But as soon as I put my foot in it to accelerate, it sounds just like a little kid who's learned to stick out his tongue and blow raspberries, thpthpthpthpthpthpthpt. The other thing that makes me think it's an exhaust leak is it's quieter once the motor is good and hot.

So I've checked the manifold mating surface on the manifold and on the block, they're true. I've replaced the gaskets on both ends of the manifold, at the head and the pipe. I've helicoiled two studs that were loose in the head, and torqued them all to spec, ditto the three studs connecting the manifold to the downpipe. I've visually inspected the entire exhaust system, I don't see any broken welds or holes rusted through pipe or anything like that. Everything looks good, and since it won't do it in the driveway I don't know what else I can do to find this. I need to find it, because if it's not an exhaust leak then something is very very wrong.

Before I break down and take it in for a smoke test, any other ideas to isolate this thing?

 

[SV_Dude]

You may have a clogged or boogered up cat or muffler. I don't know off the top of my head on how to test either of them though but maybe you can pull the cat of muffler and look inside of them with a light and see if you see any obstructions.

 

[SparkEE]

Something similar happened to me awhile ago. I just about went crazy tracking it down. Another side effect was reduced power as well so I could barely even drive the thing.

What I found - a blown gasket on one of the egr / smog pieces mounted on the back of the head that exhaust gas comes back through. That gasket went because the packing in the cat broke and rattled around sideways effectively blocking the exhaust. The pressure had to go somewhere...

I cleared out the cat (now replaced) and replaced the gasket. Solved the problem.

For your case, poke around the back of the engine and look for soot escaping from mounting surfaces.

 

[KidVermicious]

I'll check the cat, then. I don't feel like it's down on power at all, but I'm ready to check anything.

 

[Quatre Coureur]

I had a similar problem and it was a cracked exhaust manifold. The crack was located a few inches above the outlet. Ground a groove along the length of the crack and welded it up. Been good ever since...

 

[tor-redneck]

I'll check the cat, then. I don't feel like it's down on power at all, but I'm ready to check anything.

lol the only way our motors feel low on power is when they dont move!

 

[thatoneguy]

^ Lol. Unless its 2wd, a 22re always feels 'low on power'

 

[dirty dangler]

lol the only way our motors feel low on power is when they dont move!

pretty sure my motor came off the assembly line "low on power"