Pakistan secured a 108-run victory with a remarkable late burst that brought eight wickets in the last session at Old Trafford to level the two-match series.
But four of the England victims fell to what many observers felt should have been no-balls from bowlers leaving their leading leg in front of the crease.
And there was further controversy when television pictures appeared to show Pakistan captain Waqar Younis gouging and scratching the ball.
Such an action is thought to aid extravagant swing of the ball.
Similar accusations were levelled at Pakistan eight years ago in England.
On that occasion, Waqar and Wasim Akram bowled the tourists to a 2-1 series victory.
Those suggestions of foul play have always been strenuously denied, and Waqar was keen to play down the latest speculation.
Channel 4 sparked the latest row with pictures on their Monday night highlights programme.
Presenter Mark Nicholas said: “If the match referee had been watching on television, one wonders what he would have made of those pictures.”
Umpire warning
But Waqar denied the allegation, stressing: “No one spoke to me about the ball.”
And tour manager Yawar Saeed insisted: "If there was any ball tampering I would have known about it.
“There was absolutely nothing wrong. We won the match fair and square and people should be happy with that.”
The Pakistan captain did, however, confirm that umpire David Shepherd spoke to him about his players running on the pitch.
But both officials confirmed no action would be taken.
Match referee Brian Hastings elected not to discipline anybody after warning both sides about their behaviour on Saturday evening.
[This message has been edited by chilli (edited June 04, 2001).]