Current situation..
 

Maybe somebody has seen this before..? I had the pedal in the same place the whole time.

wouldn't let me attach it.. so..

My suggestion would be to pull the cluster out and check the electrical connections since both the tack and fuel gauge needles are bouncing. Could just be a dirty ground connection....something common to these two.

Are all the other gauges okay?

I hear some funky noises in the background, is the engine running smoothly or is it erratic like the gages?

Sorry, it took so long to get back.. Yeah the other gauges are working fine.. the engine on does weird stuff when the tach gauge goes funky.

After reading what Captain wrote, I replayed video with sound up and heard the engine; this is not a loose connection in the instrument cluster!

The engine sounds like it is cutting out and then back in....thus causing the bouncing needles.

Suggest checking electrical connections to the PCM, distributor, ignition module, coil, grounds....etc. Check alternator output as well.

Good luck and let us know what you find if anything.

What LannyL81 said. Friend of mine had a very similar experience awhile back. He started in "tune-up" mode, replaced his cap, wires, plugs,etc...problem persisted and he did his coil and ignition module and problem solved. this was a 00' Blazer.
As a side note, his only did this in the rain. Dry days, ran fine.

Might want to check the fuel filter for restriction, then check fuel pressure and leakdown.

It's not the fuel filter, just recently replaced that along with the fuel pump and throttle position sensor.. for the last major problem. Now that we speak of it, it's worse on rainy days.. Think i'm going to replace those 2 when I get paid.

Ahh, a key piece to the puzzle! Secondary ignition problem. Spray a mist of water around the ignition coil while the engine is at idle. Watch for spark leakage to ground. If it leaks, replace the coil. If it doesn't leak, replace the distributor cap & rotor. Use AC Delco parts and put a dab of silicone dielectric grease on each terminal, (inside and out) of the cap. If the spark plugs and wires are original, replace them as well. AC Delco 41-993 plugs with a gap of .060"

Captain, notice you say use AC Delco original parts. I have also heard others say when replacing the fuel pump be sure to use original because others may give problems. Are these things that temperamental? Just seems like any named brand good plug would work as well. No?

Hi xxEddie, looks like it could be a grounding issue, maybe. Have a friend whom had issues with his blazer for two years. He was older and didnt want to go deep on a repair. He took the truck to the dealer. After ten days of headaches at the dealer they took the entire dash out and found the big/main wire bundle where it comes close to or through the steering column brace-formed metal frame work had worn through the wire insulation and the resulting intermittant arcing was makeing big trouble.The repair was expensive and he was disgusted with the truck problems. Sold it. I would never have guessed that one.

Aftermarket fuel pumps have a list of problems depending on the manufacturer. Everything from insufficient maximum output pressure, to leaky check valves, to noisy bearings, crappy electrical connections, short life span, low volume output, to name a few ;) AC Delco & Delphi pumps are nearly identical, in fact, I've heard they come off the same assembly line. They rarely fail with less than 100K miles. Aftermarket... I've seen them fail right out of the box, and rarely make it to 100K. I will not install aftermarket pumps on a 4.3L CSFI system, even if the customer supplies it.

As for plugs, several members use NGK and have good luck with them. I don't count on luck, I use AC Delco 41-993 with a gap of .060" (that's what came in it when it was new).

So, I've replaced the vehicle speed sensor, ignition control module, and coil.. Problem still there, but not as bad.. 3rd gear is still jumpy a bit..

Did you check fuel pressure and leakdown?
Did you replace the distributor cap & rotor with AC Delco parts?

No, I haven't been able to check it, was scared to drive it off cause the gears after 2nd were being stupid.. and I haven't touched the distributor or rotor yet.

If the engine runs poorly, the transmission will shift poorly. A transmission is similar to a computer: If you put bad information into it, you'll get bad information out of it;)

Well, after I replaced these last few parts, It runs a lot better.. Just seems like 3rd gear is slipping a little bit..

I have an airtex pump in my 97 blazer for 6plus years not a problem, guess it's the luck of the draw with any part you buy, regardless of manufacturer! I would try replacing the complete distributor, can get them for $52 on ebay shipped from Skip White, better made than factory with aluminum housing & brass terminals, plus 5 yr warranty! Good Luck!

Local Chevy dealership pulled 4 codes.. MAF, EVAP, EGR, and throttle pedal sensor.. which I've never heard of.. I replaced maf with one from pick and pull.. now it acts funny if I take off slow..

#1 Check fuel pressure and leakdown, and post the results.
#2 Find out exactly what DTC's are in memory and post them.

Some vehicles have a "throttle pedal sensor", yours does not. Yours has a throttle position sensor. If the dealer doesn't know that, find a new dealer ;)

Well, been forever since I've posted updates.. replaced a few more parts, then my brother was chasing wires.. and found that my park/neutral switch was cracked, causing it to short out.. replaced that and then the shift cable became a problem.. which I just did get replaced.. the cable housing was worn into.. runs like it did when I bought it.