Strange thing happened....

[Irish1941]

Just drove 800 miles round trip up to NorCal with no problems per se but when I hit the hills the Blazer fell on it's face. 700R4 dropped to 3rd like it should. Revs went to 2500 and no more. Couldn't break 2500 with my foot to the floor. No check engine lights or anything.
Flat ground , went up to 3K/80-85 mph easy. TBI linkage moves full range with no hang ups and fuel is a solid 12psi. All sensors tested within range as well.
Pretty sure it's a distributor/ignition problem but seeing if anybody else had an issue like this before.
Oh yeah, I just did a full tune up with new MSD 8226 coil, fresh AC plugs & fuel filter.
Any ideas welcome!

 

[ktmoutfront]

Flat cam?

 

[Jester1]

any carbon tracks on cap?

or ignition module?

 

[BoondocK5]

any carbon tracks on cap?

or ignition module?

My first thought too is a secondary ignition hardware issue. Always the simple easy stuff first.

Cap, rotor, wires...

 

[Irish1941]

Flat cam would have all kinds of other issues. Crap idle, noisy valve train, popping thru the exhaust or intake. Along same line as a burnt valve.
Good thought though.
I thinking it 's the module myself.
The cap rotor & wires all new in last 8 months and all the plugs looked good with a even burn.
Now do I get a Delco or after market module? I've used Accel, MSD stuff before with no complaints but not in a TBI distributor.
Or maybe I should just upgrade the entire distributor and be done with it.
Truck has 137K on it.
Suggestions for distributors?
Thanks guys!

 

[randy88k5]

Pretty sure Advance and Autozone have a ignition module tester there. I would take it in and have them run it on their machine. However, I have seen a lot of modules pass the tests on the machine, but fail on the car. Usually heat related.

Might seem far-fetched, but can you verify the throttle valve cable is adjusted correctly?