I have an 88 Camaro IROC 350 TPI that I am having a weird loss of power problem with. For the first 5-10 minutes after I start the car, the car accelerates awesome, no problems. However, after 5-10 minutes, I hit the gas and there is very little power. If i shut the car off and immediately start it up again, the car is fine for the first 5-10 minutes, but then again after 5-10 minutes, major loss of power on acceleration. There are no problems idling, even after 5-10 minutes. There are new plugs, fuel pump, fuel filter. Rebuilt tranny this week. Changed out the coil. Didn't do it. Checked cat-it is already all cored out, nothing in it. No muffler. No engine codes being thrown. What is goin on here? Could this be a lack of back pressure problem with hollow cat, no muffler?

Anyone?

So i tested the resistance on my fuel injectors (one probe on each prong right?) and every single one came back at 6 ohms. Are they all bad? Would the car even run?

OK, so i don't think those resistance readings above for my injectors were correct. The multimeter I was using was pretty shady, and I can feel them all pulsing when I am having the problem. Also checked the TPS and that seems to be ok. I unplugged my oxygen sensor and that didn't make a difference. This is baffling, because if I shut the car down and immediately start it up, everything runs ok for 5-7 minutes.

I would think if this was ignition related (pickup coil, ignition control, etc). it would be constant and the car wouldn't run ok for a while???

And your not getting an SES light? Is the engine staying at the right temp?

No I am not getting an SES light, and I have checked to make sure it is working because when I jump the A and B ports i get the standard code 12. Coolant temp seems to be holding good. It just doesn't make sense that if i shut the car down and start it right back up (no cool down at all), it runs fine again for 5-7 minutes.???

OK, so today I ran the car in field test mode (jump pins A and B on the ECM after the car is running), which is supposed to tell you via the ses light if the car is running in open or close loop mode. It appears that my car is sporadically changing between closed and open loop mode? Is my ECM shot?

I doubt your ECM is shot. I would recommend data logging to get some accurate information about what your computer is doing. I use tunerpro and am happy with it. Also are you sure the car runs well for 5-7 minutes after restart? Have you timed it with a stop watch? Also what temperature is your engine at when this occurs (do not rely on your stock temp gauge for this measurement)?

I have watched the time with my cell phone clock and it is 5-7 minutes every time. I haven't really looked at the temp when this happens, but i don't think it is temp related because like i said when the car is hot and i shut it down and then immediately restart, it is good for like 5-7 minutes.

My '86 V6 Camaro (5 on the floor) is doing the exact same thing except I do not get the 5-7 minutes of relief. Car was fine, then 4 days ago did a U-turn in town, and out of the blue, car will not get out of its own way. I am throwing code 15 but have been doing that since bought car 8 months ago. I'll be trying a new ECU today.

I think the temperature question is a valid one. You may have a faulty coolant temp sensor, which can cause your ECM to switch between open and closed loop.
If you stop without shutting off the car when the car starts misbehaving, does it idle normally? Also, when the car looses power, does it seem otherwise to run normally, or does it start to miss or sputter?
A spark related problem can be fairly intermittent. It can be related to temperature. Ignition modules can seem fine while cold, but can crap out when the car warms up. I doubt that that is your problem though. Maybe for some reason the computer starts retarding the timing after 5-7 minutes of driving. You need to start data logging to see exactly what the computer is seeing when that happens.

When i stop without shutting the car off, it does idle normally. When the car loses power, it doesn't miss or sputter. It runs ok, with much less power.

Well as I started to work on mine today a friends made the suggestion that I pull the plug wires from the distributor one at a time while engine is idling. I was able to pull all the plug wires for the passenger side of engine with no change in idle. So it looks for me, that my fuel rail for that side is out. I did pull the plugs from that side of the enigine to verify they were firing. I need to go buy a book now to figure out were the relays are and if there is one for each side and I still need to ohm out the wires for that side as well. Good luck on finding your problem.

dont ground the A and B terminal on the diagnostic link while engine running!. IT will fry your computer. SAYS so in haynes manual first thing. THe only exception that you can ground the A and B terminals is if your car is CARBED, Correct me if im wrong. AND your Problem with your car is MOST LIKLEY Ignition related. I had the same problem. IT was a heated coil syndrome. THe coil is fine at cold start, but after 100,000 charges and discharges, it heats up and fails. Could also be the pickup coil (different coils) The pickup coil "tells" the position your crank is in, It tells you computer when to pulse the injectors. I doubt its a wire or spark plug. Testing your coil might reveal its good, but thats the problem again, only when hot does the coil fail. just athought. MAYBE of coarse, i cant see the car, but its sounds like an ignition problem.

Mine is fixed. Turns out a big wire bindle that running over the top of the tranny, just behind the motor was rubbing against a sharp edge. 1 wire for the #1 fuel injector bank shorted and took out 10 amp fuse. Rerouted and repaired wire, replaced fuse. My little V6 can lay 30' rubber tracks again =)

I switched out the ignition coil and it made no difference. When the power loss/lack of acceleration happens, there is no miss, sputtering etc. and the car idles fine. Plus, i don't think it has to do with something get hot because if i shut the car down and start it back up immediately, it runs fine for a few minutes. What about the torque converter lock up solenoid? Could this be the problem? Maybe it sticks when the tranny hits fourth, and when i shut down the car, the power being cut off from it unlocks it?

I doubt that's the problem. You can put your car in 2nd and see if power is restored in those two gears. This way the torque converter wouldn't have to lock up.
I would see what the computer is seeing, if it is going from open loop to closed loop and back to open like you are saying. Mine is a speed density car, so I am not quite sure, but have you tried unplugging the MAF and see if that helps?

I unplugged the MAF and the car runs like crap. Plug it back in, car runs fine. The more I drive it, the more it appears to be a lack of acceleration, not power, when it happens. If the car has an interruption in fuel, ignition, or anything like that, I should notice it on the tack, hear it, feel it, etc., but I don't detect any changes in the engine. It is more of an acceleration problem.

Are you saying that the motor revs freely when you step on the gas? That would be a loss in acceleration without a loss in power and would most likely be transmission related.
You can have fueling issues in the way of not having the right amount, or spark issues, in the way of not having the correct advance. In both cases I doubt that anything will show up on your tach. This will result in the engine becoming loaded and not being able to pull through, denoting a lack of power.
As far as the MAF is concerned, I think there is a way of unplugging it with the computer in diagnostic mode. I am not sure since I don't have a MAF car. Maybe somebody else can chime on this one.

Your issue sounds like your slowly losing fuel pressure, and when you restart the engine it reprimes the fuel line so your good for another 5 or so minutes... When was your fuel filter last replaced?

First, my tack is very inaccurate and reading high, so I can't really rely on it. It almost feels as if the power is there but it just isn't being transferred through the drivetrain as it should. I mean between the time the car runs fine and then when it doesn't, i don't feel or hear any actual loss in engine power. I would think I would hear the engine tone down or feel it back down or something. Fuel filter and fuel pump are both brand new.

check ur fuel pressure when the problem is present, pickup coil could also be the culprit too

I just wanted to let everyone know that I think I fixed my problem. Two days ago I gutted my airbox and installed new air filters, cleaned my MAF, and put in a new coolant temperature sensor. Everything seems to be running in order now (probably the CTS). Thanks for everyone's help

knock on wood. lets race jk