2000 Elantra losing power while driving, occasionally stalling at intersections
 

2000 Elantra GLS ~170k miles:


About two months ago the car randomly would not start. It took me forever to figure out the problem but it turned out to be the cam position sensor. I replaced it with a new unit and I also put in new spark plugs, plugs, and ignition coil. The TPS was replaced at the dealer 3-4 years ago. I replaced her fuel filter about 6 months ago.

This is my mom's car, and a few weeks ago she started to complain about sudden drops in power while driving lasting a second or two at a time. It has gotten to be more frequent, going from once a week or so to several times a day. It has also completely died at intersections on her 4-5 times now (she's said it's always started right back up). It doesn't "stumble" an then die, it just completely suddenly dies, just as if you turned the engine off.

It hasn't stranded her but she's very concerned about it. On one occasion she was at a stop sign and when she accelerated she said the car just didn't move. She pressed the accelerator several times but the car just stayed stationary (engine running, never died), and then finally after a minute or two sitting there with no movement the car finally moved.

I drove her car but was only able to replicate the drop in power while driving issue. I was cruising along at 40ish MPH and felt a surge, the tach needle fell down to about 800 RPM (even with foot still on the gas), and then after a second or two went right back up and drove along like nothing happened. I really don't know how to describe it other than the engine "cut out" momentarily. It's definitely not a slipping transmission type of loss of power (transmission is new anyway).

Now, I took her car to Idiotzone to have the codes scanned and the car is throwing no codes. I was hoping it would show a code and this be a simple fix. Nothing looks to be physically "wrong". I have also noticed that when starting her car up it starts up/runs a bit "rougher" than I remember it being. Does anybody have any idea what these symptoms could mean?

When I replaced her cam position sensor I told her we should do the crank sensor while we were at it to be safe but she didn't have the money at the time. I don't believe a faulty crank sensor should cause these issues, right?

Anybody got any ideas?

Clean iAC valve, EGR valve and throttle body, Had the same problem on a 2003 Santa Fe. The EGR was stuck and the IAC valve was very dirty.