More goal scoring success was on the cards and he remained at the club until he secured a move back to Gillingham in January 2000, following a short loan spell.
However football for Onoura was rare with the club and after starting the season alongside Asaba, he only made 8 appearances in both league and cup competitions, scoring one goal against Burnley.
After appearing six times for The Chairboys, Onuora returned to Sheffield, only to be poached by Paul Groves to sign for Grimsby Town also on a one-month loan.
After a reasonable month with Grimsby, Onuora made his move to Blundell Park a permanent one, with the club pairing him up front with Michael Boulding in the absence of the injured Phil Jevons.
This seemed to work as a jinx for Onuora, as despite earning himself a permanent deal, his performances slipped and he was singled out by the club's supporters for booing, something which the player later spoke publicly about to the Grimsby Telegraph.
Following the club's huge dip in form, Paul Groves was dismissed from his managerial duties and Onuora was to be the first player shown the door, after only signing a permanent deal four months previously.
In July 2007 he successfully completed the final part of the UEFA Pro Licence course and joined a group of only 111 coaches holding the game's top qualification.
In December 2005, Ron Atkinson, who had previously been fired from TV jobs for making racist remarks, was reportedly appointed to work alongside Onuora – one of the league's few black managers.
[11] He held the position until the appointment of Mark Stimson on 1 November 2007 and briefly remained as a first team coach under the new regime before departing approximately two weeks later.
On 2 September 2009 both Peter Jackson and Iffy Onuora were sacked from their posts at Lincoln after the board were disappointed with the club's poor start to the season[16] On 30 June 2010, he signed a one-year deal to coach the Ethiopia national team.
[19] The Ethiopian Football Federation cited disciplinary grounds for his dismissal just a month after the team's 4–0 defeat at the hands of Nigeria in a 2012 Africa Cup of Nations qualification match in Abuja.