GMC Repair: Hesitation 94 GMC 1500, vacuum leaks, exact diagnosis

Question
I have a 94 GMC Sierara 2 wheel drive with a 5.7. When I start it up, it runs perfect for about 5 minutes. As it starts to warm up between cold, and normal operating temp, it has a huge hesitation, and will sometimes backfire through the throttle body. It's like somewhere between cold, and normal temp, it's not getting enough fuel, but I can't figure it out. Do you have any ideas.

Thank you

Answer
THere are A LOT of COULD BE'S and to get an EXACT diagnosis is going to take some diagnostic procedures. Possibilities are:

1. Low fuel pump pressure/volume.

2. A residue buildup withinthe throttle plate area that needs to be cleaned using an aerosol cleaning agent.

3. I have see faulty and or mis-adjusted TPS (Throttle Positioning Sensors) that do NOT illuminate the CHECK ENGINE light on the dash.

4. EGR problems.

5. vacuum leaks.

6. exhaust restrictions.

7. Weak ignition coil.

and many others.


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