Idle lugs down/dies in gear (forward and reverse)

[j20brett]

Well, im running out of ideas here to fix my idle issue. In park/neutral, its perfect. Running down the road, its perfect. Stick it in gear with foot on the brake and it lugs down, idle starts to vary a little. Its worse in reverse, as it will die if you arent feathering the throttle. Its fine if you give it a little gas while holding the brake. Any ideas? Transmission related? Torque converter malfunction?

[Cassidy]

Massive vacuum leak from the brake booster?

[Tatsadasayago]

If not a vacuum leak, it could be your carb's idle passages are plugged.

[j20brett]

Ill check the booster, thanks!

[Gumby]

Mine would die under load especially at incline.... found out my wires were not correct. Just saying look around at Tue small stuff.

[carnuck]

Plug vac hose to booster (towards the intake but don't drive that way!~) and try shifting gears to see if it still stalls. If so, it could be too high of float level in the carb or intake vacuum leak or super stretched timing chain.

[j20brett]

Haha, well to my knowledge the timing chain is original, 1981 vintage.

[carnuck]

Look down the throat of the carb while someone sticks it in gear. You should NOT see gas trickling around the annular rings (target sights) or the float is too high. If stock carb, the spacer under it may be cracked. I had one with the hoses screwed up by the DSPO so the charcoal cannister had no rollover valve and it was drawing raw fuel straight to the intake!

[j20brett]

Thanks for all the tips. I will be digging in to it more this weekend. I pulled the drivers side plugs today just to take a peek, and well, im surprised it was running at all! Pretty fouled up. Going to clean up the other side and see what that does to it first, then start spraying around fittings looking for leaks.

[carnuck]

If you have an EGR, even without a cat they can creep open if hooked up wrong.

[j20brett]

EGR hasnt been hooked up in who knows how long.

[j20brett]

Well it still lugs down in reverse, but drive is just fine now that the plugs are cleaned up. Some were worse than this one

[letank]

looks a bit lean, are they platinum tip? not the best for our antiquated weak ignition system, I use the OEM specs #404 from champion or RN12YC.
These are mine with leaky valve seals and passed smog a few years ago:


As for the EGR when weak it can stay a bit opened.... took me year to figure it out.

[j20brett]

IMG_20150729_163359.jpg

I am running an HEI distributor, so weak ignition is not a problem. That was one of the better plugs. im happy with the color of them, i may be a bit too advanced timing wise as it pings a bit at temp on the highway.

I unhooked the egr years ago, but its still in the manifold. Does it need to be capped off?

[carnuck]

To kill the ping in my rigs I run NGK BKR6EK dual electrode, cool running plugs that were originally designed for water cooled VWs when Bosch couldn't come up with a pingless plug. That oops probably cost them $1 billion + in sales.

The EGR can only open without the vacuum hose if the cat plugs up and back pressure forces it open.

[letank]

I unhooked the egr years ago, but its still in the manifold. Does it need to be capped off?

Try to pop the pintle up by lifting the bellow of the EGR to see if the engine dies / rpm goes down. In my case the spring was weak, so it is difficult recommend a specific action. But if unsure, you can fashion a plate out of 3/8 to 1/4 steel to match the EGR gasket, and add an EGR gasket between the intake and the plate and put the EGR valve on top. Be aware that the EGR studs might be rusted so badly that the threads might be toast...

[j20brett]

The EGR can only open without the vacuum hose if the cat plugs up and back pressure forces it open.

Good info, thanks! I think the cat was the second thing that went by by on this rig