I have been having some strange issues over the past week and would like to ask for insight into troubleshooting.

1) The car will loose revs and die when rolling to a stop at a stop sign/light. It happens at random and occured once last friday, twice last saturday and a half dozen times on Sunday (including breaking down on the way home from the dyno day )

2) also at random times when starting the car it will fire and rev to about 1,400 rpm then stumble and sound like a muscle car as the revs fall to ~800 then the car dies.

3) LATEST PROBLEM: This only occured yesterday on the way home from the dyno, and subsequently as I nursed it to the garage. When shifting gears the RPM's naturally drop a bit as it goes into "N", the throttle becomes unresponsive and revs drop as the car dies (NOT fun while going 60mph).

Additional input on #3, as I nursed it home the car did this about 4-5 more times where the throttle becomes unresponsive and the car dies. I tried full throttle and it prevents revs from dropping so quickly and possible two times it would actually "solve itself" and prevent the car from dying.


What i've done so far: Pulled the plugs and plug #1 was not pretty. It had some white powder and crud around the nut portion of the plug. All four had typical white powder and detonation on the tips.






Input i've received so far:
1) One friend thinks it could be the throttle position sensor as the car hung at about 2,200 rpm at a stoplight. I'm going to try and pull it if the car will idle tonight to see if the car dies.

2) Same friend wants me to test the coils AND the TPS using a ohm meeter. However I do not know the factory impedances to test them.



Accepting any and all input to troubleshoot this problem..... And thanks in advance for any help!!!! Will be providing beers to the person who can resolve these issues or provide the "smoking gun" that leads to the resolution!

 

 

My first two steps would be to check the plugs and the coils but since you already checked the plugs I would test the coils and see how those look. I bet it's really frustrating

 

What is the test procedure on coils?


Shane: It really sucked being down to 330hp on the dyno. The only positive about the whole thing is that I was keeping up with your slow car (including its new dump) on the freeway...... You need more HP.

 

Found this online:

If the car shakes when its running, then its possible one of your injectors is not functioning. Try to feel the exhaust manifold for any cold cylinders which would indicate the problem (if there is any) Maybe have a friend keep it from dying while the exhaust manifold gets warm then feel each cylinder's runner for cold one. Also I ran into a problem with my friend in his KA DE: His car would stumble while driving and die randomly. Sometimes when he would turn it off after driving it, he couldnt get it started back up. After replacing the pump and Fuel Pressure Regulator, it ended up being the Coolant Temperature Sensor. He replaced that and his car looks like a champ. IDK about Single Cams but definitely something to look into. Who knew the coolant temp sensor is such a pain. I believe it helped with the Idle Dip as well.

Seems similar to what you are describing.

 

The easiest way would be to toss someone elses coils on there real quick and see if it clears the problem up. Thats a pretty easy way

 

your described symptoms sound like what Tyler's (sassaphrass) car was doing and it was his TPS sensor took a crap

you should try to unplug it, and see what happens, your car will still run/drive without it

 

here is where my noobness comes in... If it runs without the TPS, why have it?

Please note that the plugs came in so i'll be installing them as soon as I get home and pulling the TPS to try and resolve the issue.

Thank you all very much for the input! Happy to use any additional info you guys have!

 

Youre problem sounds alot like John (thrilla)'s problem except he doesnt have irratic idle, simply dies at idle/slow down scenarios. He tried replacing his tps with no success, so possibly something tune related. Your plugs are remarkably white, so most likely a lean condition since youre not on c16/E. Im swaying towards an injector issue.

 

Try using the stethoscope(like a doctor)and listen to the injectors. You will hear if the injector is operating normally. We had a bad injector and this is how we found the bad one.

 

Bring your car over when you have time, and we can look at it. We can swap coils, and I have a stethoscope.

TPS tells the engine how far the throttle is open, so it should still idle with it unplugged because the ECM sees (approx) zero throttle at idle.

EDIT: also, some of it is tune related, or exaggerated by it. A lot of SD cars have the same dying problem with clutch in. It's fixable.

 

The spark plugs just came in (last 4 that Oriley had on the west coast!) so i'll install them tonight and see if I can get it running reliably enough to get it up to your casa Andrew.

Luckily its sill under warranty for another 7,000 miles so if it is a coil, injector or TPS it should be covered

 

Come up tomorrow. Busy tonight....

 

Alan's bringing another big girl over?

If I can get the car running with the new plugs then i'll do a quick run around greenlake after work and head up directly afterward. Text you later tonight.

 

I had the same issues when my IACV went out... it slowly kept getting worse until the car wouldn't idle at all. Maybe yours is going out?