Ricciardo was 13th fastest in Free Practice 1 but slumped to second slowest in the second hour of running in Silverstone.
Practice 2 was complicated by late rain, which hit the venue inside the final 10 minutes and saw teams reprioritise their run plans in anticipation.
That created a discrepancy in terms of when teams completed race versus performance runs, muddying the overall picture.
“It was definitely a tricky day,” Ricciardo began.
“We did have some answers for the trickiness in FP2, we had a few issues, just we found with load – so load, in simple terms to everyone else, is grip.
“We found some issues on the car which we had for the session, so it was a bit of a bummer because obviously you still do what you can, but a bit inconclusive of probably what our true pace is.
“But equally, you look at Yuki [Tsunoda] and we’ve got some work to do as a team.
“So try and obviously sort my car out but I think in general, try and work on a few weaknesses that we saw obviously on Yuki, and get the cars better for tomorrow.”
The solution is in set-up, with changes set to be made ahead of Free Practice 3 on Friday morning.
“We’ll be good for tomorrow once we get a bit more time with the data and all that from the session,” Ricciardo explained.
“It was clear that it was evident, they could see it straight away, but trying to find the cause now is something they’ll look into.
“But confident it’s nothing too weird.
“We’ve got another session tomorrow which we will definitely need, so that’s good,” he added.
“But bit of a long day… you see Nico [Hulkenberg] in fourth, so it was a weird day.
“Fortunately, it’s not Saturday afternoon yet. We’ve got a bit more time to get it right for that.”