When her son was in pre-kindergarten, Tiffany Zerges asked the city to find out whether he had a disability and to come up with a plan to serve him.

“Although by law we were allowed a response to our request within 60 days,” Zerges said at a special-education forum this week, “60 days came and went, then 90, then 120 days.”

Once her son was belatedly evaluated, specialists contracted by the city began working with him. But those specialists rarely coordinated with the boy’s teachers or updated Zerges on his progress, she said, adding that she met with service providers just twice over three years.

“Children are losing months and even years of their education while we wait,” said Zerges, whose son is now in second grade at P.S. 361 in Manhattan. “We need changes to happen now.”

Monday’s forum was organized by a coalition of faith-based groups called Metro IAF, which hosted two similar forums last May that Chancellor Carmen Fariña attended. Though Fariña promised then that services for the nearly 188,000 city students with disabilities would improve under her restructuring of the education department, the group insisted Monday that special-education problems remain widespread.

The department confirmed that earlier this month when it released data showing that nearly 30 percent of students with disabilities, like Zerges’ son, had to wait longer than the legal limit to receive the plans that initiative support services. The report, which was mandated by a City Council law, also said that 35 percent of students only receive some of the services they require, while 5 percent — or almost 8,600 students — receive none at all.

The city has cautioned that those figures are not fully reliable because of grave flaws with the department’s $130 million special-education tracking system, known as SESIS. The online system has been plagued by technical problems since it launched in 2011, and student information remains on multiple, disconnected databases. Early on, the system’s glitches forced so many teachers to input data on evenings and weekends that an arbitrator eventually ordered the city to pay out $38 million in overtime.

At Monday’s forum, special-education teacher Megan Moskop said SESIS remains as troubled as ever.

During a recent two-hour session she spent plugging data into SESIS, Moskop said she received 41 error messages. The time spent contending with the faulty system leaves less time to work with students, she said.

“We educators want to be helping students with disabilities,” said Moskop, who teaches at M.S. 324 in Washington Heights, “but instead we’re pressured and sometimes forced to prioritize this dysfunctional data-keeping over real student service.”

Last month, Public Advocate Letitia James filed a lawsuit against the city claiming that problems with SESIS have left some students without services and caused the city to lose millions of dollars in Medicaid reimbursements. On Wednesday, the city’s Independent Budget Office said those reimbursements fell $373 million short of the city’s initial projections from 2012 to 2015.

At the forum, Metro IAF members called on Fariña to quickly initiate a series of reforms, such as adding extra members to the teams that create plans for pre-K students with disabilities and fixing SESIS.

“This is not just a moral obligation to educate every child,” said Rabbi David Adelson of the East End Temple in Manhattan. “It’s also federal law to provide decent services.”

An education department spokesman said that the city is working to improve its Medicaid claiming process and expects to see an increase in claims this year. Rule changes and a “corrective action plan” the city was required to enact have limited its ability to file claims, he added.

He also said that a multi-agency task force is looking for ways to improve SESIS, and that the department has launched several new programs for students with autism, hired 300 extra occupational therapists, and added staffers to help create learning plans for students with disabilities.

“We know there is more work to be done,” said the spokesman, Harry Hartfield, “and we will continue to invest in programs and services to ensure that every student can succeed.”