It's obviously not the modem since the issue is at the 3rd hop.
"72.129.26.177" jumps from 300 to 400ms at night upto 1,000 ms "jitter" to the east coast.
seems to be happening in the day time now as well.
C:\Users\******>tracert dslreports.com
Tracing route to dslreports.com [209.123.109.175]
over a maximum of 30 hops:
1 9 ms 11 ms 15 ms cpe-75-83-224-XXX.socal.res.rr.com [75.83.224.XXX]
2 8 ms 10 ms 11 ms cpe-24-24-194-157.socal.rr.com [24.24.194.157]
3 111 ms 102 ms 103 ms tge8-1.pldlcabl-cer02.socal.rr.com [72.129.26.177]
4 127 ms 126 ms 118 ms 72.129.26.174
5 85 ms 84 ms 83 ms agg24.tustca1-cr01.socal.rr.com [72.129.25.2]
6 90 ms 91 ms 93 ms 107.14.19.30
7 92 ms 107 ms 97 ms ae-1-0.pr0.lax00.tbone.rr.com [66.109.6.129]
8 77 ms 66 ms 69 ms xe-8-2-0.edge1.LosAngeles6.Level3.net [4.26.0.13
]
9 65 ms 77 ms 75 ms vlan70.csw2.LosAngeles1.Level3.net [4.69.144.126
]
10 61 ms * 88 ms ae-73-73.ebr3.LosAngeles1.Level3.net [4.69.137.3
7]
11 167 ms 151 ms 153 ms 4.69.132.82
12 166 ms 171 ms 165 ms ae-81-81.csw3.Washington1.Level3.net [4.69.134.1
38]
13 181 ms 189 ms 177 ms ae-82-82.ebr2.Washington1.Level3.net [4.69.134.1
53]
14 184 ms 185 ms 188 ms ae-4-4.ebr2.Newark1.Level3.net [4.69.132.102]
15 206 ms 166 ms 161 ms ae-21-52.car1.Newark1.Level3.net [4.69.156.37]
16 158 ms 147 ms 142 ms NETCCESS.car1.Newark1.Level3.net [4.26.16.186]
17 222 ms 216 ms 218 ms 0.e3-3.tbr2.mmu.nac.net [209.123.11.77]
18 235 ms 235 ms 232 ms 0.e1-1.tbr2.oct.nac.net [209.123.10.21]
19 * * * Request timed out.
20 154 ms 153 ms 149 ms www.dslreports.com [209.123.109.175]
Trace complete.