My 2003 M. Sport (180k mi) has recently started to sputter while I'm driving it down the road. It sounded like it would stall - I'll pull over, put it in Park and give it some gas. After awhile it would correct itself, but it kept coming back - only to then drive the next 25 mi. with no issue. No CEL came on so the mech. couldn't pull a code. However, when they had it hooked up to their diagnostics it sputtered for them and they traced it to the alternator. They replaced it and it is definitely running better, but I'm still getting a quick hesitation then a sputter while I'm driving. Then starting yesterday, if the engine was hot it would barely start. Luckily, I was at the mech. shop and they cleaned the IAC and it started right up, but then today after starting and stopping the car about 2 times it did it again. Gave it some gas then it corrected itself.

I've recently also had the spark plugs/wires replaced - throttle bottle cleaned. Could it be a fuel pump if they checked the fuel pressure and said it was fine?

Any suggestions?

 

I put some Sea Foam in my fuel tank during my last fill up and for the first 80 or so miles, I noticed an improvement. I wasn't getting the hesitation/stutter and the car was running smooth. However, as the tank gets lower on gas I'm starting to notice the hesitation is starting to come back - just not as strong.

Again, no lights on the dash are coming on.

 

Usually when there is hesitation, the CEL will come on. Have you checked if all lights on the dash work? turn the key in the on position but dont start. Make sure all the lights work.

 

Yes, my dash lights work. Car has been running fairly well, except for the occasional hesitation/sputter...until today. Ran the car for some errands - let it sit for just under 2 hrs. Took it out again and FINALLY the Service Engine Light came on while I was sitting at a red light. As soon as I put my foot on the gas to go, the car stalled. Started right up, but everytime I stepped on the gas it would stall. I was able to get through the intersection by barely pressing on the gas. Made it to my destination - car sat for about 30 minutes - started up and ran just fine. Took it to Advanced Auto and the code pulled was for the MAF sensor. We got lucky and a Honda mechanic was in the store so he came out and took a look and determined that MAF sensor was not the actual problem (he had a diagnostic gadget with him). He also said it pulled 2 more codes (P0113 & P0107). Then we told him that the alternator was just replaced so he tried one last thing - he disconnected the battery and the car sputtered immediately - indicating that our alternator was bad...again. He said that could have triggered the other codes.

Taking it back to the shop on Monday. My biggest concern is that it's something else causing the alternator to keep dying. I'm also wondering if we need the OEM alternator.