I have an intermittent problem with the engine falling on its face at 4,000 RPM under load (in gear and a decent amount of throttle). It feels like I’m hitting a RPM limiter - the engine gets fuel starved (I’m assuming this), the RPMs will drop a little, it will rev back up, fuel starve, repeat.

I first experienced the problem months ago but it only happened once and didn’t happen again. It’s become more frequent as time has progressed to the point of it almost always happening now.

Earlier today I pulled the MAF to check it out because it is exposed to water thanks to the ram air hood. The wire looked ok and I shot some electrical cleaner through it. I reinstalled it and took it out for a spin and the engine fell on its face at 3,500 RPM.

What other sensors would cause fuel starvation at a specific RPM? Could this be a wicked vacuum leak?

The car idles/drives fine up until whatever RPM fuel is cut. Up until today it’s always happened exactly as the tach hits 4,000.

The trans swap did nothing to increase/decrease this occurance. The engine is a more or less stock L98 with 110xxx miles on it. 88 means MAF, not SD.

 

I am curious about your transmission swap, what did you go from/to and also did you install the trans yourself or did a shop do it? I ask this because I had a very similar problem only my problem was caused by the knock sensor pulling about 10-12* of timing out because of a harmonic that occurred at a certain rpm due to the header vibrating against the frame. So if your trans mount bolt and torque arm bolts are not torqued properly you could possibly be getting a harmonic from transmission vibration causing the knock sensor to pull out timing. Just a thought. Good Luck.

 

A 700r4 to a T-56. It happened before the trans swap so I'm going to deem it unrelated. I'm almost 100% sure that it's MAF related. The ignition doesn't drop off (tach stays up) and fuel pressure stays constant (just finished driving around with a fuel pressure gauge taped to the windshield). Taking timing off the engine wouldn't kill it like this does. The engine will rev down during one of the occurrences even if you hold the pedal to the floor. Once it drops far enough it will surge back up normally till it runs into the wall again and revs back down. Repeat until I shift.

It is somewhat weird that I can walk it past 5 grand without any issues if I'm being extremely gentle on the throttle but then again it's not pulling as much air as it would be at WOT. At WOT it will happen anytime between 3.5 and 4k rpm.

 

Can you tune your own chips? You may need to modify the MAF tables, as well as the MAX Airflow vs RPM table.

 

maybe worth hooking up a fuel pressure guage and testing your ignition.. I had similar problem but I have my stock transmission. When was the last time you did a full tune up? IE. ICM, Cap, Rotor, Pickup, Fuel Filter