My car began having problems yesterday and dont know the cause. I was driving home when it began sputtering whenever i pushed the gas anymore than a quarter the way. It idles perfect, and doesnt seem to have any problems thru 3rd gear under regular acceleration. The problem starts in 4th and continues in 5th when i get up to around 35 to 40 mph. When i push the gas it just shakes and sputters. Im thinking maybe injectors. not sure tho Any help would be great. Car is 1999 Civic Si. thanks in advance

 

See if the problem occurrs when you floor it from a stop pointed upward on a steep hill. Bogging down when you give it alot of gas under load can happen when you are almost out of gas or have a problem with the fuel system. It can also happen when you have a weak ignition. Ideally, you should check the fuel pressure with and without the regulator vacuum hose attached and check the spark at all four wires with a new or known good plug or a spark tester. This kind of problem is usually from something cheaper to fix than the injectors.

 

replace your plugs and wires