Well this happened Once before, about 6 months ago and never happened again until yesterday on the Highway traveling on the dreaded memorial day weekend.

So what normally would be a 2-hour trip from NJ to CT, took me almost 4 hours due to traffic! And this issue has only happened when the car has been in traffic stop and go etc. Finally got up to cruising speed for awhile, at about 70mph with my foot on the accelerator (no cruise control activated) and the car suddenly "bucks" and drops speed with my foot still pressing down! . So i had to quickly merge over to the breakdown lane. Let the car sit for a few minutes, then got back on the highway and got back up to 70mph. After about 15-20 minutes, it happens again! Weird. This has only happened when the car was in stop and go traffic on my 2-plus hour trips and only on the highway. Also, the red "Check engine" flashes on for a sec and goes away when this loss of power occurs.

Anyway, Spoke to a mechanic friend and he says its probably a switch, throttle etc since the car is drive by wire and to get a scan done. So has anyone else ever experienced this ? I have to drive back to NJ tuesday and hoping this doesnt happene again until after i go to the dealer ! Thanks in advance for any input...

 

I had a Jeep that had those exact same symptoms and it would only come and go for the longest time. It ended up being a faulty Throttle Positioning Switch (TPS) which finally starting failing on a regular basis. After fixing that it was fine.

 

^ Hey thanks for the input!

Its funny you mention it, because a mechanic friend said it could very well be a TP sensor, and it sure sounds like it could be exactely that. It never happen in city driving, nor at steady cruising speeds. Only happens when i get caught it heavy highway stop and go traffic, like i did this past weekend. And ive only experienced heavy highway traffic like that twice this year.

I have to wait till tommorrow to go to the dealer since theyre closed today for the holiday, and i will get them to run a scan and get a code.

 

My brother's Lexus IS350 suffered through the same problem but it was somewhat worse. His car wouldn't go beyond something like 10mph. The Lexus dealer did a scan and came up with a code for the TP sensor.

All they did was clear the code and the car was fine. My brother, who's a Acura tech BTW was somewhat concerned b/c all they did was clear a code and not replace any parts. But since the car is still under warranty and Lexus was footing the bill, he pretty much can't say much.

 

go to an auto zone for their free scan. get the code (s) and report back .

 

Update: The car is at the dealer in CT where my Dinan stuff was installed. They pulled the car and found no fault codes! I dont get that, and i thought that once the "Check engine" light flashes, even for a sec, its recorded. So now im waiting to hear what they come up with next week.

 

What year is your car? I had intermittent TPS issues (throttle would go nuts all on its own when holding steady (even with CC on) fortunately my issue went away on its own over a year ago

 

A very similar thing happened to me yesterday. I'd been on the highway only about 10 minutes before running into traffic. A few minutes later, I'm pressing down on the accelerator to move forward and nothing is happening. It felt like the car just lost power. I didn't notice an engine lights come on. I turned the car off (cause it wasn't going anywhere) and sat (this really went over well as I was in the center lane!). A minute later I turned it on and it was fine. I was getting off at the next exit anyway and the car was was fine the rest of the day. I thought perhaps it had overheated (as it was about 96 degrees out and I had the a/c cranking) or maybe I had hit the cruise control by mistake (at a really low speed), but now I'm worried I have this throttle problem.

 

^ Yes exactly my symtoms. My car is a late production 2003. What really sucks is, because the dealer didnt find any fault codes, they dont know what to replace and they want to give my car back to me! So what if this happens again? And im sure it wioll happen again, because i commute between CT and NJ where im living now once a month or so, and there always traffic on 95!

 

Did this happen to you while in traffic or after encountering traffic? It seems like my throttle gets heated up and goes haywire after sitting d=so long and in "stop and go" etc. And then the danger is if it happens on the highway and suddenly i lose power, and someone is right behind me going 65 plus!

 

In my situation (on the Jeep) it actually ended up being the connection to the TPS sensor. The sensor it self was fine. In diagnosing it I had the TPS sensor replaced and it did it again a while later. It ended up being the wiring harness to the sensor. The dealer would not replace just the connector because the part only came as the an entire electrical system wiring kit (read super expensive). I went to a junk yard and cut off all the wires to the TPS unit and had then splice that in and it worked perfectly for another 100,000 miles until I sold it and I sure its still fine.

Point is... Possibly you have a connection issue to the TPS?

 

There was a TSB around on this topic. We had the same kind of thing happen (car looses power on highway, goes into limp home mode). The dealer ended up replacing the wiring harness to fix it.

 

This is my fear! My car is a 2007 and it's only 3 weeks old... I was on the highway at normal highway speed for about 10 min., then I hit stop and go highway traffic which I was in for about 5 minutes when this happened.

The car has been fine since and I did the engine check and it said "check ok". I'm calling the dealer tomorrow... I have to call them anyway as I was rear ended today (yippee).. though not related to to this problem. The person behind me just decided they were about done waiting for the red light.

 

Really ? Wow, maybe my SA didnt check the TSB's. I know replacing a whole wiring hardness is a big job. Maybe they are saving that for the "Worst case scenario". I will have to mention that to him in case he doesnt know about it. It makes perfect sense, in fact someone i spoke said that it "could be your wiring" but im hoping its not something this drastic. Thanks !