I'm having a very odd power loss after the first few minutes after start up

A little background info

last summer I redid the head gasket on my 22RE. In addition to having the head milled, I installed a complete exhaust system, new short ram intake and used block off plates on EGR system. The breather vales on top of the valve cover, one was blocked off and the other was replaced with breather filter.

Since the rebuild I've had a lot of power issues with the truck. At first I played with the timing to try to get it close as I can. I ended up taking it to my mechanic and had him time it and check the valve timing. There was still a lack of power and I was mostly sick of the head ache and started to drive my beater car around.

I've been driving the truck on and off since the rebuild and have noticed that the power loss is only a temporary condition. When the truck is first started (with out without the block heater plugged in beforehand) it will run and drive fine with a high idle for about a minute. After that whether it has been driving or just warming up the idle starts to drop off and wants stay just above stalling. If I happen to be driving at this time, you can feel the power loss as it starts take more throttle to keep the same speed, the engine bogs down and does not want to accelerate in gear or neutral. it will slowly build RPMs with 1/4 throttle but one up to speed it will slow and bog going up inclines like there is a drop in horsepower. After 10 minutes of driving the power returns and I can drive it normally

It seemed like an electrical issue, so I had the alternator and the battery tested. they both cam back as good. the batter wasn't tested under load so I might still be needing one. But other then that, I am out of ideas.

 

Stalling: Correct the idle adjustment. You need to do this before and after setting the ignition timing.

EGR: The computer expects that to be there, and adjusts for it even if it's not.
http://www.autoshop101.com/forms/h56.pdf Page 14 "Factors that degrade emissions & drivability"
http://www.autoshop101.com/forms/h61.pdf Page 1 "EGR impact on engine control system"

Machining: Do you still have the paper work for this? How much was removed,and what model year is the engine? The factory height was heads 3.290(75-84) 3.130 (85-95), blocks 11.280 (81-84) 11.090 (85-95). If you removed as little as 0.010 it will effect the valve timing. OHC really aren't designed to be machined, they're ment to be replaced.
LCE has an adjustable cam you can look into.
http://www.lcengineering.com/LCTechP...TechNote48.htm


Inspect your coil, and coil/sparkplug wires, also don't overlook the oxygen sensor the TPS or the VAFM.

 

the coil, rotor, cap, wires and plugs were all replaced. I dont have the paperwork for the head milling so im not sure how much was milled. The EGR computer might have something to do to it. What I am finding weird is that the power loss is onlty temporary from starting about a minite after start last only untill about 10-15 minutes of running. Could this be the computer readjusting to the for the lack of EGR?

 

It is temperature dependant then yeah? it's either a temp sensor (ECT. engine coolant,CST cold start time,THA air temp) or something in the wiring. Maybe but not likely metal expansion.

 

I've thought about it being temp depedant but wouldn't having the block heater plugged in at least caused some sort of difference. its around -10 to about +20 F here in the winter.

 

You said it starts fine w/o the heater. Did I misunderstand that maybe?

Also confirm you did the timing and adjusted the warm idle please.

 

It does start fine without h block heater going and it has the same power loss after a minute either way

I had all the timing done by a shop and they confirmed they do it warm