HELP! 1992 Suburban Extremely Frustrated

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junkmanjunior

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Picked up a 1992 K1500 Chevy Suburban about a month ago. Had been setting.about 2 years only to be started and moved occasionally to go to dump or mow. Test drove after jumped battery and ran poorly not necessarily a miss but no lower end power or acceleration felt like your were pulling a heavy trailer etc. Accelerating would pick up eventually but it would almost want to red line when shifting. Now I'm no mechanic but inclined enuff to do a lot of things myself or have a general idea to look for a problem or the root of it.

So I bought it limped it home assuming a tuneup might fix the issues. Started with plugs wires cap rotors oil change and fuel filter. After that same thing but managed to put about 400 miles on it. Then replaced entire distributor idle air control spark control (knock sensor) throttle position sensor pcv map sensor water temp sensor egr valve fuel pump rebuilt tbi and set time with computer unplugged and reset the computer. Of course there is checking in between some of those parts to see if it made a difference.

Now it fires up and basically runs better than it ever has aside from an idle surge that goes away quickly. But when you put it in gear it wants to die (and sometimes will) unless you keep giving it gas. If you try to drive it, it has even less power and slower acceleration than before I even touched anything.

I've rechecked timing more times than I can count checked voltage on tps and iac getting plenty of spark and plenty of fuel. Had a vacuum gauge on it reading about 17-20 in park at idle but drops down to 4 or 5 in gear. I really don't know what else to do. Could it be torque converter? TV cable? Transmission sensor? Timing chain? Bad brain aka ECM? Worn lobe or lobes on the cam?

Any help is appreciated don't want to keep throwing parts at it.
 
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90halfton

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Checked plugs? Fuel psi while under load? Have you put fresh gas in it? Compression test? Used an ohmmeter on the tps while moving the throttle back and forth to ensure it's not giving funny resistance in places?
 

Dr.Zoom

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Vacuum lines and pcv? I had a pcv hose that would collapse and cause stalling/stumbling.
 

matrix

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I've rechecked timing more times than I can count checked voltage on tps and iac getting plenty of spark and plenty of fuel. Had a vacuum gauge on it reading about 17-20 in park at idle but drops down to 4 or 5 in gear.

The massive drop in vacuum leads me back to timing.
What is your procedure for checking the timing?
Any chance of using another gun for comparison?
 
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