97 Burb wont start - Heavy Crank

[chargerrich]

97 GMC Burb 5.7L Gas When turning the key it cranks fine for about 1 sec followed by a "run down" or "heavy" sounding crank but wont fire. This can be repeated with each try. I thought it was the battery due to the heavy run down sounding crank but that was replaced with no luck. I was thinking fuel pump, filter or maybe even an ignition control module, but given the distinct symptoms I though perhaps someone else had this problem. Any help is appreciated. Thank you.

[collinsperformance]

have you checked to verify it is getting fuel? spark? is there gas in the tank? can you her the pump run? id the check engine light on? is there any codes in the system?....mike

[chargerrich]

Update - The trucks Cats had gone out and apparently melted literally my O2 sensors. All is working now.

[collinsperformance]

great---thank you for the followup. this will help someone else that may have this issue and searches the site for help....mike