Hello everyone,
Not sure if this should be in "Under the Hood" or here since it falls under both. I am trying to figure out why my car is running so poorly. I tried to check a lot of things first so that this wouldn

 

The VT box infiltrates a few circuits in the ECU. When not in boost, it's supposed to just let the ordinary signals get through without interference, however, if the box is faulty, it will interfere when it's not supposed to. It could be NOT letting he ECU get the signals it needs.
The car's ECU can go bad. This is the worst case scenario when it comes to random misfires. When all else has been eliminated, it's the ECU that needs to be replaced.
The only way to know for sure if either one is the cause of the problem is to substitute a known good one.

 

xviper,
Thanks, that's what I thought.

What is your thought on the TPS? Doesn't that cause poor running at lower RPM's? Also, can you explain why when I replaced or swapped out the MAP, sprak plugs and coil packs, it felt much better for a few days and then gradually felt worse again?

Thanks for your help.

Anthony

 

If the TPS is "off", I would think that you would see this in the way the engine revs up even in neutral. Does it act weird when just bringing up the revs without load?
As for the rest of it, it's a mystery to me. When you swapped out all that stuff for new, did you happen to reset the ECU? I'm wondering what would happen if you did nothing else but just reset the ECU.
Could it be that the wiring connections of your VT black boxes has degraded? Check them.

 

xviper,
I just went out to check. I should also mention that it doesn't start up as smooth. It also doesn't quite idle like normal either. It has the same feeling without load. Also, I revved it lightly with the hood up and listened. There is a ticking sound comin from the throttle body/intake manifold area. It is definately not coming from the engine. I had a spun rod bearing before and that was noticably coming from the engine. When I use the wire to rev the engine, I can feel the clicking in my hand. I wonder what that could be.

I reset the ECU when I swapped out the coil packs. Maybe I should try again.

One thing I have not done yet is check the connections. That will be next I suppose.

Thanks,
Anthony

 

You could have a case of seriously maladjusted valves. Also, the thing on or near the throttle body that would tick and interfere with idle would be the Idle Air Control solenoid. These have been known to tick when they are not working correctly.
Then, you could have a bum knock sensor, but this usually generates a CEL.

 

Ahh, more possibilities. The block has 6k, the head has 76k. So maybe it is time to adjust the valves anyway. They inspected the head when they had the engine apart. Would replacing the throttle body replace the Idle Air Control solenoid too?
Thanks,
Anthony

 

If it is indeed the TPS, would getting a Pro flow throttle body work? I think they take cores and bore them out. I wonder if they check the TPS though. Might be nice anyway with the SC.
Anthony

 

No. It's a separate part on the side of the intake manifold.

That's an expensive way to find out it's not the problem. You should first check TPS to make sure it's operating within the proper voltages.

 

I thought the Pro Flow throttle body was $155? That is much better that the $495 hardtopguy quoted me. I wouldn't buy one unless I knew it was bad of course. I was just saying that I would also gain the increased flow as an extra benefit. Of course, the TPS that came with it would be from whatever car it was on so I would not be certain if it was in good shape.
Anthony