Alright, I had my new exhaust on and welded (headers, hi flo cat, catback), as well as the ultimate TBI mods. I drive the car home from the exhaust shop and it runs great....smooth idle, more power then stock, sounds great, etc. I drive it for about a half hour that day, off and on.

I drive it to my friends house and shut it down, and when we get back in it, whenever you start from a stop, the engine almost dies, and it has NO power...even when trying to accelerate it is slow and sluggish.

Now when I start it up, the engine almost dies, then it gives itself more gas, then almost dies, etc until it warms up. Then it runs ok, unless you give it any gas, in which case it almost dies when you let off the gas.

I checked all my spark plug wires, and its not running choppy like it is missing a cylinder.. Ive also replaced the EGR valve along with a few other sensors in the past few months...does anyone know what would cause this?

 

It always works out that way. You go to a friend's house to show off your new mod and Mother *#&@er!!!! The damn thing starts messin' up.

About the only thing you can do is take it back and have them look it over to make sure they didn't move/disconnect something and forget to return/reconnect it. L0RD know I've done that numerous times.

Have you checked for codes? Or are you actually getting any codes? The symptoms you are describing sound like a lean mixture caused from a vacuum leak or the O2 sensor has been knocked loose or has just gone bad. Code 44. I once had a 90 1500 pick up that did the same thing. I just drove it like that, but it wasn't a performance car either.

AJ

 

I just remembered another reason I drove it like that. It didn't make any sense.

I checked all my hoses along with the base gasket under the TB. Everything there was fine. And it didn't make sense that it was the O2 sensor either since it only did it when it was in open loop mode. In open loop, the O2 sensor is totally ignored.

Maybe just try disconnecting the batt. and maybe that'll clear it up? Worth a shot I guess. A shot in the dark, but no less it's a shot.

AJ

 

Every time I've run into the same problems you have, it has been linked to the ignition setup. Since you have headers on there now, you need 90 degree plug wires anyways. Headers release a lot more heat into the engine compartment then your old manifold did. Though you may not see anything wrong visibally, the heat from the headers can still soak through the rubber to the wire, thus raising the resistance level drastically=poor performance and the symptoms you have. I would recommend Accel 8.8mm or Bosch 8.5mm wires. The worst that could come from this is a new set of high performance wires.
Also, try reseting the computer by disconnecting the battery for a minute.

 

thanks for the advice guys...to answer some of your questions, the o2 sensor is new, and is unharmed, its not throwing out any codes...and all the exhaust shop did was 2 welds....i did all the other work, and triple checked to make sure everything was still connected.

I also did make all the boots 90 degree boots, however i will check the resistance of them all tomorrow, as well as reset the computer...which by the way hasnt given me any codes.

 

if it drove fine before, could it possibly be something related to the temp of the air your engine is getting, if it was HOT when you tried to drive it with no power, that could be part of it.

 

ok...I replaced the plug wires with good MSD ones, unplugged the battery for awhile, and it is still having problems.

Let me clarify what its doing....

On startup it idles fine after a bit, but anytime you give it gas, when i lets off, the car almost dies, but then it gives itself gas. If I try to move in gear, it starts moving ok, but then almost dies after like 2 seconds...even if let out the clutch at 3k rpms.

I tries this with the o2 sensor plugged in and unplugged, and it acts the same, except the computer stays in open loop with the o2 sensor unplugged

 

When doing the ultimate TBI mods did you also make the regulator adjustable? Maybe the setting was disturbed somehow.

It could also just be a coincidence that the fuel pump is going bad or that your fuel filter picked this time to clog up.

Lastly... (I know this sounds stupid)

Is there gas in the tank?

Your symptoms sound like a lot like a fuel pump that is sucking up the last dregs. If so, that is additionally bad because the fuel pump depends upon a constant stream of gas for cooling.