Nice lo-miler D- you gots there. You've hit a couple of 'bout 15 key culprits. Search 'Warm Off-Idle Stumble' on your browser. Or, do an Advanced Search with those keywords here - VARE REE common:

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And consider a new mech. You sound already better with diagnostics.

 

When engine is cold the PCM functions in OPEN loop and ignores feedback sensors like MAF, MAP, etc
Once coolant temp gets over like 140-160 deg the PCM would switch to CLOSED loop and adjusts fuel, timing, etc as sensors report.

If this only happens in closed loop then look at sensors, if having a MAF, clean it well with a MF cleaner,
Look for any type of air leak from the aircleaner to the throttlebody and intake manifold

Really need to use a good OBD scanner and see if other sensors are reporting and if within proper operating ranges like the MAP, O2 sensors, timing, fuel injector ON time, etc

Else look for a exhaust leak that is upsteam of O2 sensors that is causing them to report AFR incorrectly
or maybe O2 sensors are too old and need to be replaced.

 

When engine is cold the PCM functions in OPEN loop and ignores feedback sensors like MAF, MAP, etc
Once coolant temp gets over like 140-160 deg the PCM would switch to CLOSED loop and adjusts fuel, timing, etc as sensors report.

If this only happens in closed loop then look at sensors, if having a MAF, clean it well with a MF cleaner,
Look for any type of air leak from the aircleaner to the throttlebody and intake manifold

Really need to use a good OBD scanner and see if other sensors are reporting and if within proper operating ranges like the MAP, O2 sensors, timing, fuel injector ON time, etc

Else look for a exhaust leak that is upsteam of O2 sensors that is causing them to report AFR incorrectly
or maybe O2 sensors are too old and need to be replaced.

I forgot to mention that my mechanic did clean the MAF and inspected the throttle body, he said it was pretty dirty but it still ran the same way afterward. I have had an engine light come on here and there but it always goes away within a few minutes.

 

Any codes? Mine did that and it turned out to be the fuel pump, well sort of. Someone had replaced the pump but had forgotten to tighten the clamp on the line from the pump to the feed line and it was just barely on there. I'm guessing it was spraying fuel back into the tank. My fuel pressure was at about 25 PSI at idle and would not go higher. It eventually wouldn't idle at all and started throwing all sorts of codes, including random misfires. I found this only after a new MAP, EGR valve and solenoid, coil and another module, all four oxygen sensors and catalytic converters. Granted some of those parts needed changing but I was chasing a ghost for the longest time until the fuel pump showed itself.
I'd suggest a fuel pressure test just to be on the safe side.

 

I’ve had an engine light come on and off for a few minutes at a time, I just haven’t gotten the code read, it is OBD 1 so I have no idea what kinds of places would have a scanner to read the code.

 

I have a 1994 Fleetwood and when it heats up, it bucks at low speeds up to about 5 mph after letting my foot off the brake, once I get up to speed it is smooth as can be. I had my mechanic look at it and he found nothing wrong and just replaced the fuel filter, I changed the egr valve and spark plugs (before I brought it to him) and it still has the same exact issue. I have no idea what's wrong with it, (I've been told bad opti, plug wires, etc.) The issue has not gotten worse or better it has stayed the exact same for a month or so. (104k on it)

If anyone has any suggestions or questions let me know please!
Thanks

Good Morning,
Can you check and tell me the error code that shows on the display?

 

^ ^ ^ ^ This

If not already familiar, Diagnostic Trouble Codes can be read from the HVAC panel:

How to pull codes (DTC's), list of OBD1 &amp...

To check for Diagnostic Trouble Codes stored in the computer, turn the ignition on, then hold down the OFF and WARMER (for digital dash) or OFF and passenger-WARMER buttons (for analog dash) or OFF and "Info ^" buttons (if you have temperature dials) until all of the dash lights come on. The...

www.cadillacforums.com

 

What's the fuel pressure? One of the first tests your tech should have done. Key on, then while starting, then while idling, then while accelerating from stop (zip tie the gauge to the wiper arm).