I was having a problem with my my car surging at low idle and occasionally dying. I figured it could have been my EGR valve so i took the upper plenum off in order to change out the EGR but i couldn't because the bolts were to tight so i gave up and put it all back together. After i put it all back together and started driving it shot the code 45(rich exhaust) and i started getting only 9MPG instead of 14MPG. The Also it would really die at low idle unless i would hold the gas at the same time as the brake, and the surging got worse. I got into my haynes manual and have tried everything it says to do which includes the evaporative charcoal canister, the ECM and Prom, the HEI Shielding, And throttle position sensor. None of these fixed the problem however i did find that if keep the TPS unplugged it runs almost like it should. If anyone has any ideas that would be great because everyone i know and 2 mechanics can't figure it out.

 

Did you try changing your TPS?

 

Change O2 Sensor
Check for leaks around Fuel Pressure Regulator

Check Fuel Pressure.
A bad FPR can cause an increase in FP,
which can cause a code 45.

Change TPS

 

92 sleeper is absolutely right because i had almost the same problem but mine i would de-celerate off the gas and fuel would pop out the exhaust with loud bang..... normally its either your FPR or TPS sensor screwing with the computer.... its not a O2 sensor i can tell you that :-)

 

I did change the O2 sensor and the TPS. One of the mechanics did a fuel pressure check and said it was fine, however after he would release the pressure from the system it would slowly climb back up. He had me replace the fuel filter and that wasn't the problem either. The Fuel Pressure Regulator does not appear to have any leaks.

 

HMM tough one only thing else i could think that would have a major problem with fuel would be emissions system like EGR valve...

 

only thing else i could think of would be manifold air temp sensor i had one go bad and would idle very rough changed it on plenum and ran alot smoother

or EGR went bad....sounds like maybe overloading with gas?

 

Since you're getting a code 45, that says your O2 sensor is reading a high voltage signal and is telling the computer the fuel is rich. At which time it should be signaling the fuel supply (M/C solenoid, injector time pulse width) to lean out the air/fuel ratio. If the O2 sensor doesn't see a change in voltage input in a certain amount of time, it sets the code. That means your O2 sensor is working properly as long as the M/C dwell or Pulse width is changing along with it in closed loop. Create a vacuum leak to add air and see if the O2 voltage changes. Of course a scan tool would be the "Best" tool for the job.
Or maybe the Air Temp sensor didn't get hooked back up on install. The first thing to do with the EGR valve, is to test it to make sure it works properly, before tearing the whole upper plenum off. Rich exhaust is due to 3 things. Fuel supply(carb/fi), PCV crankcase contamination, Evap system malfunction.
Pinch off evap hose to the intake manifold and remove the PCV valve from the valve cover leaving it connected to the manifold. The only thing left to cause a rich mixture is the fuel supply.
Fuel injectors have a tendancy to leak over time. If one goes, expect the rest to go.

EGR opening at idle would cause a high HC reading, resulting in a lean mixture because the fuel isn't burning to create CO. So the EGR shouldn't cause a rich mixture. And it wouldn't have that bad of effect cruising down the road, if that's when the light comes on. The light should reset after turning the engine off, come back on after a couple minutes of the computer seeing the problem. If the light comes on and stays on after startup, it's probably a wiring fault.

 

I had disconnected the Evap System about 4 weeks ago and put rubber caps on the ends of every thing that needed it. I replaced the PCV about 6 months ago. To be clear are you saying to remove the PCV from the valve cover or removing the hose from the PCV in the valve cover. Also i have triple checked to make sure every thing is plugged in correctly.

 

The PCV system clears the inner block from combustion chamber fumes that get by the rings. By removing the PCV valve from the valve cover and leaving it connected to the hose, your engine is now taking in "fresh air" instead of crank case fumes. The PCV air intake is a metered amount designed into the system. By removing the valve from an fuel source, you eliminate it as the cause of the CO problem.

 

ok, I tried unplugging my PCV Valve from the cover and blocking off the evap system. There was no change. Before i put this post up i had gone yo a mechanic and he did a fuel system diagnosis and said they were all fine. Is there possibly anything else that could be the cause, or did the mechanic just not do a very good job checking.

 

I got a fuel pressure gage and checked my fuel pressure only to find that it is where it should be. So does that rule out the fuel pressure regulator?

 

This is very wierd. When I got a code 45, I changed my TPS and it fixed the problem. Is there a chance that yours needs to be adjusted properly? Just curious.

 

There didn't seem to be a way to adjust it. It can't move.

 

I took the camaro to a chevrolet dealer yesterday. They had it all day and call me at the end of the day to tell me that cylinders 2,4,5 are not firing at idle and in order to further diagnos it they wanted to take off my injectors and check them for $200. I needed the car back and they had already charged me $100 just to diagnos it as far as they had so i went and got the car. One of my mechanic buddies told me to pull off the distributor cap and check the rotor for corrosion, because it didn't make sense that only those 3 fuel injectors would get clogged. Any thoughts?

 

Ohm out the injectors. If they are stock Multec's they should ohm out at 16-17 ohms. If they ohm lower but above 12 they can be cleaned and saved. If they are lower you need new injectors.

You should check your Cap and rotor and make sure they are good. Ohm out your spark plug wires too. You might have a couple gone bad.

You need to make some checks before dumping money into parts.