Car Idling Problems on 1996 Honda Accord

My car has had several parts replaced, no codes register when I take it to the shop, but it still idles down pretty low after driving it about 10 or 15 minutes.Spark Plugs,wires, fuel pump, filter and toon up have all been done. What could it be.

2 answers 1 comment
A tune-up? By whom? Check the fuel linkage to TB. The cable linkage should be tight enough to have a defection - maximum of 1/2 inch and check idling.
Sir need to know make and model and year of the vehicle to even attempt an answer.
96 honda accord 2 door coupe with a vtec engine