My car's an '88 Trans Am 305 TBI. It has recently started idling sort of choppy when in OD at a stop. Also, you can feel it 'surging' at around 40. That's the best way I can explain it. I thought it was like a fuel filter or something, but I then though I'd get some fuel injector cleaner and see if that helps. Anyone have any thoughts?? Thanks in advance.

 

Change your fuel filter and try the injector cleaner, neither can hurt anything and could potentially fix your problem. Since you have tbi, you can observe the spray patters of the injectors to see if they need to be cleaned. You want them to be very uniform, or they could be semi-clogged. I lost a cylinder a couple weeks ago because one of my injectors became clogged.

 

Does anyone know what else it could be? I've replaced the fuel filter, and used 2 bottles of the STP fuel injector cleaner. How long will it take to get the injectors clean, if this is the prob?

 

Does it idle funny when cold? Look at the most likely suspects. Have you changed the oxygen sensor ever? When was a tune up done? Any work been performed on the car that could have caused this?

You're supposed to mix a bottle of injector cleaner with a full tank of gas, pouring the injector cleaner in before you fill up. When that gas is gone the cleaner should have done its work.

 

It idles funny all the time when in gear at a stop. But you can feel it 'missing' when at speed also. I have put one STP bottle in after I filled it up. Then put another one in at about half a tank and filled it up then. Well, we got the car in October of last year, so I've never changed the O2 sensor. Where is it, how much does one cost, and how hard is it to do? Sorry, but it's kind frustrating. Thanks