QuestionI just had my fuel pump replaced on my 95 Astro van because it was getting hard to start and idling pretty rough. Well the starting issue is fixed but I can still feel the engine not running smoothly at idle…you can feel it shake and lurch like it misfires. not constant but maybe every few seconds I can feel it. I have had the fuel filter replaced, the plugs the wires. Any ideas on what could be making it not run smoothly at idle?
AnswerYou have not told me the mileage of your van. But you say that it just was tuned-up. I would suggest replacing the distributor cap and rotor regardless if it is related to your complaint or not. They get very corroded and should be replaced at tune-up.
Ok, taking into consideration that the tune-up was performed correctly and there is no misfiring I would have to lean towards a fuel injector problem. The Central Port Injection unit on your vehicle have been known to fail. I have replaced so many of them. I'm assuming you do have CPFI (you have not told me what engine you have).
My suggestion to you would be to purchase 4 bottles of Chevron Techron Plus at any parts store. This is the only fuel injection cleaner approved by GM.
Fill your tank up and dump 2 bottles of injector cleaner in your gas tank. Drive the vehicle normally and do not add gas until it's below a quarter tank, and then repeat the process again with 2 more bottles of Techron. I've had good luck doing it this way.If your engine performance improves then it was most likely the injectors. If there is no improvement it still could be bad injectors or even something else that would need to diagnosed.
A little rough idle is a normal characteristic of this vehicle so I would not get too worried if it's not that bad.
Always use only Top Tier Gasoline(Go to TopTeir.com) to prevent further injector damage and use the Chevron Techron Plus every 3000 miles.
Feel free to get back to me with more questions.
