I’d start with the P1351 since it’s being reported, but it could be setting due to extended cranking times. Did you check the fuel pressure? It could be bleeding off.
The GM manuals can be downloaded at the link below.
Over the years I have collected a bunch of GM service literature. Links to PDF Scans of service and STG manuals and a links to the Parts manuals. You'll need the FREE Adobe Acrobat reader to open these files. Get it directly from Adobe here {http://get.adobe.com/reader/} If you're not...
www.gmt400.com
It will have the diagnostic procedure for each DTC. Here’s the P1351 for a 98, maybe it will help.
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