Losing Power when pedal gets near floor

[papa smurf]

Replaced the valve cover gasket recently (requiring me to move the air box)

Since then, the engine loses power when I depress the gas pedal more than 75% to the floor. It runs fine until that point, but once I put the pedal on the floor the revs fall and engine sounds similar to a rough idle.

For instance, in 4th gear on a flat surface I can get the engine up to about 4000 RPM, then when I push the gas pedal in further the revs fall back toward the 2500 mark.

Any ideas? Going to look at it tonight and need to get the car ready to handle a weekend at pismo.

FYI: 1984 stick shift

[ARCHINSTL]

Breather tube and PCV hooked up (and latter clean and clicking and its grommet tight?)?
Little vac tube leading to HIC in bottom of air cleaner housing hooked up? This usually causes idling probs, but it could under load as well - unsure about this, though.
Tom M.

[So_Powerful]

I had that same problem on my trip to Kelowna though it only occurred between Edmonton and Red Deer. The rest of the trip was fine. I'm beginning to think it was only because it was a really windy day and tercels are like sails when a good cross wind is gusting across the praires. I've also encountered winds that would make the nose of my tercel dive to the ground an inch or more. Other then the wind I just thought it was carb problems which makes me want to get a Weber even more.

[Petros]

sounds more like you need a new fuel filter (which could be coincidence to you removing the valve cover), it is partially plugged and allows low speed driving normal, but at full throttle(high fuel demand), it falls short. Could also be coil going out, that will get to the point where spark is weak when you test it.

There is a FSM procedure for testing coil. The fuel filter is an easy and low cost swap. Also check for leaks in your fuel lines, up stream of the fuel pump may not leak fuel, but suck air in and result in fuel starvation.

The air filter housing could also be blocking the choke to it will not open all the way if it is not installed properly. Also check the vac line under the air filter is connected properly or it will cause big vac leak.

Good luck.

[papa smurf]

Little vac tube leading to HIC in bottom of air cleaner housing hooked up? This usually causes idling probs, but it could under load as well - unsure about this, though.
Tom M.

Also check the vac line under the air filter is connected properly or it will cause big vac leak.

Nailed it. Hose seemed very loose and now this baby's runnin' smooth.

On a unrelated note...what are the most common oil leaks on these cars?

[4wdchico]

An oil leak at the dizzy is very common.

[takza]

Valve cover gasket...by far?

[Petros]

I would say the valve cover gasket. Right now I have an oil leak from my fuel pump. I recently made 2 new gaskets, and used sealant, and I still get a leak from my fuel pump. Is there a place oil can leak out of the fuel pump? If so I might swap it out with a spare one I have.

[ARCHINSTL]

Don't they all have a vent hole underneath? I just replaced a mech pump on my '88 Dodge/Mitsu 2.6 (a real PITA!) p'up. The oil was literally squirting out of that hole all the way back to the firewall - a real mess!
And Yes, I did change the oil.
Tom M.

[Petros]

Don't they all have a vent hole underneath? ...The oil was literally squirting out of that hole all the way back to the firewall - a real mess!

That is what I suspect is happening on mine, but why? Is this normal, or is something internally wrong with my fuel pump to allow oil to leak out the vent hole?

[splatterdog]

Mech pumps always have a breather hole. Typically there are 2 seperate diagphrams in a mech pump. One keeps oil contained, the other fuel. If you have oil coming out it might just be a matter of time before the fuel one ruptures and gas comes out the hole and also pushed into the crankcase. It may still run while filling the engine. I've seen 2-3 gallons come out of a few v8 engines back when mech pumps were still popular.

[Petros]

My second car I bought for $100, a 1965 volvo 122S, with a thrown rod but otherwise in excellent condition. I rebuilt the engine and got it running good, and on my first oil change (a 500 mile "break-in" change, when we used to do that), it came out like black gasoline, not oil. It also smelled of gasoline too. It was the fuel pump diaphragm that failed and allowed gas into the crankcase.

That was why the engine through a rod on the previous owner, and good thing I caught it early. I was in high school, and it was an early lesson learned about the risks of mechanical fuel pumps, it ran just fine with the leak fuel pump diaphram.

But I was not aware that there was a way for motor oil to leak out of the vent hole in a fuel pump.

[ARCHINSTL]

Interestingly on the previously-mentioned fuel pump replaced on the 2.6 Dodge/Mitsu engine...it, too, ran fine with the leaky diaphragm. When I noticed the leak (how far/long did I run it like that - maybe a couple of hundred miles ???) - I remembered some advice about leaky pumps mentioned on our site - I checked the oil, and the level was at least a half-quart over "FULL."
So I just knew that extra amount was gasoline. But upon draining and sniffing, it did not have any gas odor...
Hopefully I did no harm to the 2.6 engine; the truck is a rustbucket POS, but the reman Jasper engine has only about 8K on it; we shall see.
Tom M.

[papa smurf]

I'll trace out that damn oil leak at some point here. Pissing me off.

Many thanks to Tercel4WD. The SR5 absolutely killed it at Pismo!!! On arrival, my crew (repping a new Wrangler, a 2WD Explorer, and a lifted SX4) was worried whether my car would even make it down the beach. All of their cars had gotten stuck just driving to the campsite.

We had the car packed with gear, 3 people, and had an extra 2 drunks standing on the bumper. Got to the spot easier than any of the other cars...by a landslide. That EL gear is money.

The crazy thing is, after ripping it to shreds over the weekend...it's actually driving better than ever this morning. And more than one issue with the car have miraculously fixed themselves. The first time I've ever really off-roaded the thing and I am impressed.