Please Help me Diagnose my problem!!

Ok, so I have been trying to get my 89 s10 4.3 4x4 to stop bogging down and loosing power. Here is the history of the vehicle. I am not a mechanic, but I am pretty a pretty good DIYer and can do most jobs
that involve basic skills, tools and elbow grease.
I bought the truck about 2 years ago. It always ran pretty good, passed inspection with no problem, but seemed to hesitate a little when stepping on the gas (ie to merge into traffic) and lacked power on hills. The truck has a 2" body lift and 31" tires, so at first I kinda thought that the larger tires would slow it down a bit. It never really had any problems, I always just wished it had a bit more pep. So over the past 2 years I have slowly replaced most of the sensors and little parts that are prone to cause problems. Yes I checked the codes, keep getting a 32 I believe. But I figured at about $30-50 a part if I slowly tried to replace them during quarterly oil changes it would keep it pretty inexpensive and I might get lucky.
Everything was going great, love the truck. But over the past month or so, the problem has just gotten worse. To the point now where I feel the harder I step on the gas the slower the truck goes, especially at low speeds. If I have to climb a hill from a stop, often I have to drive in the shoulder because she just wont get about 30mph until I get on flat ground. I hear what sounds like a vacuum leak especially at low speeds and with the pedal lightly depressed. As I play with the pedal the vacuum sound seems to match the pedal. I have inspected all of the visible vacuum hoses (replaced a few) but cannot find a leak. The original air box was replaced before I bought it with a 10" KN Open Air Filter sitting on top of the motor. When I try and isolate the sound under the hood, all I hear is the air rushing through the TBI, the vacuum leak can really only be heard while driving in the cab. So I am not sure if there is a hose that I cannot find or see, or that the sound I am hearing while driving is just the intake and the sound is unrelated to my problem.
Some days I feel it runs better than other, but I can't really isolate any conditions that it performs better in, and it might just be in my head. I don't really notice a difference when it is warm or cold. She Idles fine and drives fine at light throttle and highway speeds. Say I am on a flat road going 50 she drives fine, not prob but as soon as I start up a hill, I start to slow down. So I step on the gas a little, she starts to growl real loud, but slows down more. As I approach the top of the hill and let my foot off the gas it starts to pick back up again.
Seeing how the weather was nice I thought I'd give her a tune up and see if that would help, so I have all new plugs, wires, cap, button, fuel filter, pcv. However it had no affect on performance. I have an appointment for my mechanic to look at it later in the week, but it would be nice if I could figure out what was wrong myself. As I mentioned before I have replaced most of the typical parts that go, most of which were original or in poor condition when I changed them
So over the past 2 years I have replaced the 02 sensor tps sensor map sensor coolant temp sensor Replaced the 160 thermostat which it came with, with a 180 (I know stock is 195, please dont flame me about that have already been through that) The fuel pump I was told was replace right before the guy sold it too me but I haven't verified that, nor checked fuel pressure. (I have ran out of gas twice since buying it, but not recently)
I have run a bottle of HEET through the tank see if there may be water in the gas, and then replaced the fuel filter. I have Amsoil Power Foamed it, as well as run some Chevron Techtron through it since I have owned it.
The only things I can think of left are. I had a radiator crack over the summer on the drivers side and it was leaking coolant for a while, right over the EEC cansiter. So maybe some how that is contaminated. Anyway to check without just replacing?
The Cat converter is clogged. It doesn't glow red but I havent' checked any temps around it.
The fuel pump is bad.
Loss of compression or bad valves.
Some sort of tranny problem.
If anyone has any suggestions or advice I would greatly appreciate it. I apologize for the essay but thought I would give as much info as possible. Any Ideas? vacuum hoses I missed? Thanks
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snipped-for-privacy@smcm.edu wrote:

Have the exhaust flow tested, the sound and symptoms your seeing can easily be caused by a clogged cat/muffler.
What tires does the tag say came one it and what gear ratio do you have? The 31" tires are probably not helping with performance and are putting a strain on the transmission (which isn't all that rugged to begin with). Consider a gear change front/rear to help that and put the engine back into the proper RPM operating area.
Also put a 195 thermostat in it. The lower temperature means the engine stays cold for a longer time and that adds more gas to the exhaust which causes the cat to burn hotter and burn out. It does NOTHING for performance on a computer controlled engine. And can actually be considered tampering with emissions equipment (violation of federal law = 10,000$ fine) since the computer uses engine temperature to regulate the EGR and fuel delivery. Not a flame just the facts.
--
Steve W.
Near Cooperstown, New York
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In article < snipped-for-privacy@v67g2000hse.googlegroups.co m>, snipped-for-privacy@smcm.edu wrote:
<snip>

Disconnect it and plug the fittings, test drive.

Remove O2 sensor, install 18mm fitting, connect pressure gauge, start engine, measure back pressure.

Connect fuel pressure gauge, start engine, measure fuel pressure. Alternately; connect a scan tool to ALDL -or- connect a DVOM to the O2 sensor circuit, monitor O2 voltage at WOT, voltage should NOT trend low.

Perform compression test, perform cylinder leak down test.

Is the transmission coming out of lock up when you add throttle to climb a hill? Can you force a downshift when you tromp the throttle? Is the detent cable adjusted correctly, is it broken?

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Have you tested the engine vac readings? This would certainly help a whole lot in terms of pinpointing. I can tell you that I had similar symptoms on a 95 when the hose to the 4WD vac switch was torn off. As for hearing air rushing in the cab, do you have a leak at a blend door or behind your climate control switch? I think on your truck those items are vac controlled. If you don't have a vac gauge, go pick one up and post the results by tee-ing into a vac hose in front of the engine. Mist some carb cleaner around your main vac lines and see if you can get the motor to rev a little, that should help pinpoint in (although noise in the cab is a good start for sure).
I agree with Steve that the tires with stock gears aren't helping. Good luck, Andrew.
On 1/12/08 6:43 PM, in article snipped-for-privacy@v67g2000hse.googlegroups.com,

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It turns out it was the cat. Had it tested and it needed replacing. The vacuum is coming from a bad gasket between the TBI and the engine. I guess a little too much powerfoam. Now she runs better than ever and the Flowmaster 40 I had installed when i bought it, now rumbles nice. I was really disappointed when I had it installed, I needed to replace my muffler for inspection and went for it. But it didn't sound that great. I guess my cat was clogged not allowing it to breathe. I'm surprised that passed inspection. Anyways that seems to have solved my problem, I plan on replacing the gasket sometime soon. Have a few questions about spacers (another thread) and then hopefully that will take care of all the engine probs. Next on to the front end!!!!
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