Why cant I find a 2.3l replacement pass side exhaust manifold?

[STPL]

1994 2.3l 5spd XLT. I had to replace the entire exhaust system last year from the down pipe to the muffler, which went off without a hitch except for the studs on the exhaust manifold snapped off. I ended up drilling them out and throwing some bolts in there, but it just wont seal correctly and I think this is leading to a stumbling idle issue. Im trying to find a replacement exhaust manifold and cant seem to find a single one online. I would rather get a bolt in replacement than end up going to the junkyard and getting another rusty one that will probably give me the same problems. I found one on summit racing, but it says it fits 1983-1992. Did the 2.3l change after 92, or will that one work?

Any ideas on where I can order one from? OEM part number: F37Z9430D

 

[scotts90ranger]

The difference in the newer one is in the EGR tube, the newer one has a flow meter (the two tubes going to the sensor mounted on the firewall or rear lifting eye, don't remember) in line. It's been a while since I've seen a stock manifold to remember what both look like, some of the newer ones are fabricated instead of cast so probably weigh 20 pounds less.

I did a quick look at NAPA, Autozone and Amazon and I'm not seeing anything either, apparently they don't break...

Honestly it would have to be a fairly big leak right next to or before the pre catalyst oxygen sensor to cause an issue, an air leak on the intake side after the MAF is going to make a bigger difference, or a dirty MAF. From personal experience at work the biggest issue with the flared exhaust is the area around the seam weld in the pipe on a hard flare like the 2.3L uses. A lot of times the flare will not crush the weld and the work hardened and heat treated from use cast iron exhaust manifold will not conform to the weld seam.

 

[Dirtman]

You should try finding a drivers side exhaust manifold...

 

[STPL]

The difference in the newer one is in the EGR tube, the newer one has a flow meter (the two tubes going to the sensor mounted on the firewall or rear lifting eye, don't remember) in line. It's been a while since I've seen a stock manifold to remember what both look like, some of the newer ones are fabricated instead of cast so probably weigh 20 pounds less.

I did a quick look at NAPA, Autozone and Amazon and I'm not seeing anything either, apparently they don't break...

Honestly it would have to be a fairly big leak right next to or before the pre catalyst oxygen sensor to cause an issue, an air leak on the intake side after the MAF is going to make a bigger difference, or a dirty MAF. From personal experience at work the biggest issue with the flared exhaust is the area around the seam weld in the pipe on a hard flare like the 2.3L uses. A lot of times the flare will not crush the weld and the work hardened and heat treated from use cast iron exhaust manifold will not conform to the weld seam.

I also find it very strange that I cant find any. The truck starts strong when cold, but then the idle degrades after a few minutes. When I give it a tiny bit of gas it smoothes out, then letting off the gas causes it to idle rough. Ive replaced the IAC valve, the 02 sensor and the EGR valve but nothing fixed it. I think I can hear a slight exhaust leak, but nothing major or super obvious. I was thinking the mating flange from the manifold to the downpipe isn't sealing properly and sucking in air when idling, throwing off the computer. Thats why im going after a new manifold, does that make sense to you?

 

[Shran]

Sometimes the fuel injectors will sound like a small exhaust leak. Rule that out first. I suppose you could try to smoke test the exhaust and EGR plumbing, that'll tell you for sure if it's leaking where you think it is... but even a new manifold may not fix that completely if the flange on the exhaust pipe itself is worn or damaged.

Your idle issue is pretty common on 2.3 trucks. I've had similar issues on all three of mine, it's very hard to nail down exactly what it is. I've read quite a few threads on this issue over the years and haven't found anyone who has actually fixed it yet. I have just been living with it and replacing bits and pieces here and there.

 

[Curious Hound]

I have some 3.0l exhaust manifold you can have. Just cut off the extra parts and plug the holes with toilet paper.

 

[Ramcharger90]

Just get a header instead. Emissions on a 94 whole even checks that any more?

 

[Shran]

Just get a header instead. Emissions on a 94 whole even checks that any more?

I don't see where he mentioned emissions testing at all? Three points for you to consider here:

1: Emissions testing is a reality that many in this country cannot avoid and CT appears to require testing on anything anything newer than 1992 at this point
2: This is not an emissions issue anyway, it's a driveability issue, I'm guessing you have never had to deal with it but it is VERY irritating when you pull up to a stop light and it shakes like crazy and/or dies
3: These newer 2.3 trucks already have a tubular manifold from the factory, it looks like a shorty header, you gain nothing with an aftermarket header.

 

[Dirtman]

3: These newer 2.3 trucks already have a tubular manifold from the factory, it looks like a shorty header, you gain nothing with an aftermarket header.

You can gain alot with an aftermarket header on a 2.3. You gain constant leaks, rust, and the fun of changing gaskets every 2 months...

 

[STPL]

Sometimes the fuel injectors will sound like a small exhaust leak. Rule that out first. I suppose you could try to smoke test the exhaust and EGR plumbing, that'll tell you for sure if it's leaking where you think it is... but even a new manifold may not fix that completely if the flange on the exhaust pipe itself is worn or damaged.

Your idle issue is pretty common on 2.3 trucks. I've had similar issues on all three of mine, it's very hard to nail down exactly what it is. I've read quite a few threads on this issue over the years and haven't found anyone who has actually fixed it yet. I have just been living with it and replacing bits and pieces here and there.

Replacing bits and pieces here and there is exactly what I've been doing all along. I replaced the EGR, IAC and 02 sensor within the past year and no change. The idle problem doesn't seem to be damaging anything, I sent an oil sample to blackstone labs twice and they said everything looks good on their end. I'm not SUPER concerned about it, but I would like to figure it out so the truck runs better. Sometimes I think I can hear a small exhaust or vacuum leak but other times not. My next step is to fix this exhaust manifold leak and then maybe throw a MAF at it, but those aren't cheap.

Whats a good way to smoke test the motor?
I might resort to a junkyard to find a decent manifold, but thats always a gamble.

 

[Dirtman]

A local machine shop should be able to resurface the sealing surface of your current manifold fairly cheaply.

 

[Shran]

I imagine you could use something similar to that method, but push it backwards through the tailpipe. It would leak past any exhaust valves that are open but if you have enough smoke in there it might push out of somewhere else too if there is a leak.