I was out all day yesterday and driving the car normally then at one point I decided to get on it and the car fell flat on its face, just like when I used to hit fuel/boost cut from overboosting in my older toyota days but the gas pedal was not responsive.
Difference between this and when I hit boost cut in past on other cars is that stepping on the gas didn't move tach. I pulled over quickly shut off and restarted, check engine light came on, I gave it a little gas then when I started moving same thing happened, falls flat on face and gas pedal wasn't working. Each time I tried to restart, the idle was rough and a few times it shut off.
After multiple attempts to get it going I waited about 10 minutes, gave it another go and it started and stayed idle. I rev'ed it out and it felt smooth so I decided to try to make it to my uncle's house who was a few minutes away.
It stayed on but when I got to my uncle's house I tried to take it around the block, gas worked but absolutely 0 boost as if a boost hose came off but when I looked underneath everything was in place.
I stayed there for a couple of hours to let the car cool down before I made an attempt to get home. Although check engine stayed on it made it home no problem. I drove slow and tried not to press the pedal too hard until I got home, then when I was a few minutes from home I stepped a little harder and could see a little boost on the gauge this time.
When I got home I pulled out the durametric and below are the codes:
P1554 - Malfunctioning throttle,
P1266 - fuel cut (I guess the car went into safe mode)
P0121 throttle position sensor and
P1095 which I guess because of bad MAF reading errors relative to throttle.

Has anyone experienced this? Car is stock, no tune exhaust or mods.
It appears to be a bad throttle position sensor and is this sensor on the gas pedal or Throttle body or do I need to change both?

Thanks in advance for your feedback

 

That happened to me once when I left the pressure sensor on the y pipe disconnected. Didn't check codes though. Just plugged it back in and it was fine. Not saying that's the problem because like you I would look at the tps.

 

MAF?

Loose hose connection not obvious from a visual?

An electrical connection related to throttle position/MAF/boost?

The suddenness of it sounds like a boost leak to me, but I could be wrong.

Ed

 

Thanks, I don't think its a boost leak or a popped off hose because after 2 hrs the car ran fine and made boost like normal.
If the hose popped off, it would keep the same symptoms.
I also replaced the MAFs last month but I unplugged and re-plugged the connectors when It happened, I also thought about bad MAFs or bad connection also.
Codes point to changing the Throttle Valve assembly since I can't just replace the TPS.
Gonna order one today $235 on Pelican.

 

Hello @YJosephTT.

In the attachment you will find some info about E-Throttle

Regards
Hans

 

Thank you much for this.

 

Just wanted to update on this past issue of no Throttle response, the readings I believe were false and triggered from overheated ecu.

I changed the Throttle valve assembly and the pedal just to be safe and the same thing happened again.
This time when I noticed it starting to act funny again and logged it with durametric.
What I could see from durametric was the pedal potentiometers were responding when I stepped on gas but the pedal value, actual plate values and throttle plate potentiometers didn't change.

What was in common with previous times was the car had been running for a while and was hot. Oil and coolant temperatures were fine but the car was idling and/or in traffic when it would begin. I got the feeling that this is heat related and not an issue with actual Throttle valves, possibly a bad connection but somehow relaed to heat.
So I went to pull the ecu and check the connectors to the harness and it was very clear the entire rear firewall area by the ecu was extremely hot.
The ECU was also very hot to the touch. I unplugged the battery and removed the ecu.
I let car cool then reconnected everything but left the ecu downside up and exposed and removed the rear padding over the rear where the ecu sits.
Since then I've been driving the car this way trying to get it to replicate the problem and its been driving smooth. Even sat in traffic almost hour and no more problems.

It seems like the ecu was overheated and causing it to glitch out.
So far I can't get it to come back, but ecu is still exposed in the back.
I plan to send it to Marski to check what kind of tune might have been on it.
I suspect maybe the car had a tune once and reverted back to a bad stock base tune before I got it.

I'll update as more along the way.

 

Wow, great diligence in finding this. I had no idea the ECU could get cooked by the engine heat.

Ed