1975 280z won't rev past 2k to 3k rpm???

[280z1975]

My 1975 EFI 280z is having trouble running past 3000 RPM's it will rev up then almost no power. You can floor it and nothing is going on. It all started after I filled up at a gas station and then BAM, it's power died about 2 miles down the road. I don't think it's bad gas as it was a good gas station. The only thing I can think is that I gave it diesel instead of gas, but that was on my mind when I filled up and I made sure to grab the gas pump ... any idea's on the problem.

Also, it will start fine when cold, but when the engine warms up it has trouble kicking over. If it helps I can make a small video of the problem to post along with this. Any ideas out there on where to start ....

[sblake01]

How's your water temperature sensor? When I had that problem it turned out to be a bad connection at the sensor.

[mel marabante]

sounds like a problem i had 2 years ago. i fixed the most obvious ones i can think of which was to eliminate the gas possiblity to no avail. the culprit was the elec. module next to the distributor. the engines gets hot and the darn thing acted up. when i poured little water on it to cool it down, it started right up. good luck

[sblake01]

Mel, you have what is listed in your profile as a '1979 280Z'. I'm sure you mean 'ZX'. He has a 75 and his ignition module is inside the car in the passenger footwell and not subject to engine heat. Look like you're bored and trolling through old threads. If you're going to do that, add something pertinent or just let it go.

[sblake01]

Err....okay.

[mel marabante]

stephen, my apologies. i didnt know the rules on this site. really new when i posted it. wasn't even paying attention to the date. just putting my 2 cents in, sounded like it was worth 2 cents too. by the way, it is 1979 280 zx but that wasnt one of the options given when setting my profile. the option was 79 280z then 1980 280 zx.

[280z1975]

Hello all ... well I wanted to update you guys on this post and get some feedback on directions. Work for me has been SO crazy that I haven't found the time to get to working on the car till this week.

So I hooked up a pressure gauge to the vacuum lines to test the pressure in the system. When the car is idling it is ok, but once you hit the gas it goes down to nothing. This has lead me tells me there is a vacuum leak in the system but I don't know how to start to find it.

Any suggestions?

Also, would a bad valve cover seal or exhaust manifold seal lead to this problem? Both of mine could stand to be changed I am sure, with the exhaust manifold the worse of the two.

I haven't driven my car in 4 months and I'm itching to get this problem fixed, so any help would be great!