S-Type revs while coasting
#1
Guest
Posts: n/a
![Default](/forum/images/icons/icon1.gif)
Hi Guys!
I did a search for "revs on its own" and "revs by itself" first but couldn't find a post with this issue. The quick backstory is this... I had my engine light come on a few weeks ago and along with that came the shuttering, sputtering, and hopping up and down when idling. From what I read in the posts, is that it's best to replace ALL the ignition modules (mine had the yellow stickers on the tops). So over the weekend, I replaced allthe ignition modules along with putting in brand new NGK Iridium IX plugs in my 2002 S-Type 4.0L V8.
The good news is that the car now runs GREAT and doesn't shutter at all (which was quite embarassing when I had passengers in the car). But the bad news is that after three "cycles" of cold starts, the engine light is still on and a new problem has surfaced. I now notice that if I'm coasting down from, let's say 40-55MPH, and get below that speed with my foot off the gas, the engine will rev all by itself between 1,000-2,000 RPM for about five or six times. It literally revs on its own up to around 2,000 RPM for a second then comes back down to around 1,000 RPM for a second and then back up to 2,000 RPM and so on.
Haven't a clue as to what this might be, but I'm guessing that perhaps that's why the engine light is still on?
I did a search for "revs on its own" and "revs by itself" first but couldn't find a post with this issue. The quick backstory is this... I had my engine light come on a few weeks ago and along with that came the shuttering, sputtering, and hopping up and down when idling. From what I read in the posts, is that it's best to replace ALL the ignition modules (mine had the yellow stickers on the tops). So over the weekend, I replaced allthe ignition modules along with putting in brand new NGK Iridium IX plugs in my 2002 S-Type 4.0L V8.
The good news is that the car now runs GREAT and doesn't shutter at all (which was quite embarassing when I had passengers in the car). But the bad news is that after three "cycles" of cold starts, the engine light is still on and a new problem has surfaced. I now notice that if I'm coasting down from, let's say 40-55MPH, and get below that speed with my foot off the gas, the engine will rev all by itself between 1,000-2,000 RPM for about five or six times. It literally revs on its own up to around 2,000 RPM for a second then comes back down to around 1,000 RPM for a second and then back up to 2,000 RPM and so on.
Haven't a clue as to what this might be, but I'm guessing that perhaps that's why the engine light is still on?
#3
Guest
Posts: n/a
#4
Thread
Thread Starter
Forum
Replies
Last Post
Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)