Anyone with an opinion welcome. Car stuttering at high rpms.

[Senor Grizzly]

Update: Just want to thank everyone who has replied. I haven't fixed the problem but its great to hear other peoples opinions and suggestions!

 

So i just want to start off by saying I am in no way an experienced mechanic. I am having a problem with my 1977 Datsun 280z and am willing to hear anyone's thoughts. So I haven't driven this car much. i bought it and it had a leak in the exhaust manifold. Since i had to take it all off i decided to buy headers. While removing the EGR tube, the tube was damaged so I decided to remove the EGR. I remove the EGR use a block off plate from a Z store. I capped off the vacuum that leads to the egr.

Now for the problem. When in the driveway the car sound great. I can rev it as high as i want and it sounds perfect. when driving around normally it feels fine as well. The problem comes when driving a bit faster or opening the throttle quickly. When im driving and pass about 4000 rpms the car starts to sputter and i can smell gas. It feels as if its not getting enough air to burn the gas in the cylinder. If im drivng fast and step of the clutch and rev theres no problem. the sputter only happens when im actually putting gas to the wheels. Does anyone have any idea what can cause this? The fact that it acts so well in the driveway or with the clutch in throws me off hard.

 

 

Edited April 7, 2017 by Senor Grizzly

[Reptoid Overlords]

I just recently went through a similar issue, but it was at a lower RPM(around 2k) I found that my throttle valve switch was improperly adjusted. I have a ZX, and I believe the TVS switches are similar for your car with the exception of you can take yours apart without drilling out any rivets. Check the FSM under fuel and see how to adjust it with an ohmmeter. Hopefully that is a good start.

[siteunseen]

Breaking up under a load can be a bunch of stuff.  How long since you did a tune up, new rotor button and a distributer cap?  It could be jumping spark under the cap.  

 

[Mark Maras]

 IMO, to eliminate the obvious, (no offense to the Cap'n) a complete tuneup is the first thing to do. It should be done sooner rather than later. I had one of those high RPM misses years ago. I convinced myself that it had to be something beyond the obvious (apologies again) and after much head scratching and many w.t.f. moments, it was finally cured with new plugs. 

[FunkytownZ]

what is the condition of your rubber boots?

1) air filter to air flow meter

2) air flow meter to throttle body?

I went from one wrapped in duct tape to the new part below and it solved similar issues.  The EFI bible also lists this as one of the first things to check on "stumbling under acceleration"

 

Edited April 6, 2017 by FunkytownZ

[Senor Grizzly]

12 hours ago, Reptoid Overlords said:

I just recently went through a similar issue, but it was at a lower RPM(around 2k) I found that my throttle valve switch was improperly adjusted. I have a ZX, and I believe the TVS switches are similar for your car with the exception of you can take yours apart without drilling out any rivets. Check the FSM under fuel and see how to adjust it with an ohmmeter. Hopefully that is a good start.

i bought a new throttle position switch

i adjusted it to the sound of the engine. if i move it any more in either direction the car starts to act up instantly

[Senor Grizzly]

11 hours ago, siteunseen said:

Breaking up under a load can be a bunch of stuff.  How long since you did a tune up, new rotor button and a distributer cap?  It could be jumping spark under the cap.  

 

all three of those parts were bought new

[Senor Grizzly]

4 hours ago, Mark Maras said:

 IMO, to eliminate the obvious, (no offense to the Cap'n) a complete tuneup is the first thing to do. It should be done sooner rather than later. I had one of those high RPM misses years ago. I convinced myself that it had to be something beyond the obvious (apologies again) and after much head scratching and many w.t.f. moments, it was finally cured with new plugs. 

thanks for your input

when i got it running i replaced the oil and got new spark plugs

[Senor Grizzly]

2 hours ago, FunkytownZ said:

what is the condition of your rubber boots?

1) air filter to air flow meter

2) air flow meter to throttle body?

I went from one wrapped in duct tape to the new part below and it solved similar issues.  The EFI bible also lists this as one of the first things to check on "stumbling under acceleration"

 

the boots are brand new

they were pretty beat up before and patched with silicone

[gwri8]

As you might have guessed, pictures can help a lot by showing things not mentioned.  Is there any way of you can show your engine and the work you have done so far?  Could provide obvious/not so obvious clues.

[Senor Grizzly]

1 hour ago, gwri8 said:

As you might have guessed, pictures can help a lot by showing things not mentioned.  Is there any way of you can show your engine and the work you have done so far?  Could provide obvious/not so obvious clues.

sure things. here are a few random angles

[JSM]

You said you got new plugs, how do they look now? Does it run ok when it's cold, then when warmed up it starts to miss?