Hesitation always while under load

[JERRY SPINOSA]

1993 GMC 5.7 YUKON.The hesitation occurs with engine hot or cold AT ALL THROTTLE POSITIONS. Also where can i buy a live data scan tool for OBD1 and 2.Can the engine coolant temp sensor be diagnosed without live data accurately.Or maybe you can lead me in the direction for the hesitation issue?This engine has TBI. Gas filter and air filter were replaced.

THANK YOU, G.MAN

Topic

[Igor]

I spent a lot of time to fix this kind of problem. Provided that no DTCs found (no fault codes).
Finally, MAF sensor replaced with new one, and problem (almost) gone.
There is still some slight hesitation of RPM , but not noticeable.
In my case it was Hot Film MAF. I guess it was very sensible part…
If you get a scanner, check the Short and Long Term Fuel Trim, in my case the computer was always decreasing fuel supply (which means I did not have vacuum leaks and air was OK)

[EricTheCarGuy]

I find it’s usually best to start with the basics when dealing with performance issues. I cover the steps with useful videos included here.

http://www.ericthecarguy.com/faq/solving-automotive-performance-issues

Try to keep things simple before you go after complex theories about this sensor or that. Throwing parts at a problem gets expensive.

Good luck and keep us posted.

[Author]

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