Ok, when reading this thread I came across the following:

I've been having a stumbling and hesitation problem when I make any fast throttle movements, and while looking at my tune in tunercat, I came across the following:

In the TPS Threshold Vs. RPM for Power Enrich Mode table I find the following:

RPM TPS%
0 60.2
400 60.2
800 60.2
1200 60.2
1600 60.2
2000 60.2
2400 60.2
2800 60.2
3200 60.2
3600 50.0
4000 39.8
4400 30.1
4800 19.9
5200 19.9
5600 19.9
6000 19.9
6400 19.9

In the TPS Threshold for PE vs. RPM, (high cool) table, the settings are:

RPM TPS%
0 39.8
400 39.8
800 19.9
1200 10.2
1600 10.2
2000 10.2
2400 10.2
2800 10.2
3200 10.2
3600 10.2
4000 10.2
4400 10.2
4800 10.2
5200 10.2
5600 10.2
6000 10.2
6400 10.2

The Coolant threshold for high temp PE TPS Threshold constant is set at 116.75 degree celcius.

Would this explain why I only get the stumble after the car has been running for a couple of minutes?? When I do a cold start it's fine, but once it starts warming up any fast/deep (opened farther) throttle movement will cause the car to stumble/hesitate, which I believe is a misfire due to too much fuel being dumped into the mixture for some reason.

Am I on the right track here or just out of my mind?

 

The numbers I posted were for a stock '94-'95 PCM tune and they were the "low coolant" settings. These PCM's also have the high coolant setting at 151* C (304* F) and the %TPS to enter WOT for the high coolant were all zero'd out.

It makes sense, they want the car to enter PE as normal but if the engine temp goes sky high they want it to run in PE mode constantly to help cool it down (although by 304* it's getting a little late). I might move the high coolant temp settings down

You're high temp settings are set to 242 * F so if your engine is getting that hot I believe temp is the problem, not going into PE mode

fwiw, in PE mode the engine should be running rich which typically masks drivability problems anyway.

Sorry bud

 

Dang, thought I was on to my problem. Well, back to the drawing board......

Stoopid never running right car.

Thanks for the help!

 

Is this a stock tune with few modifications, a borrowed file, or what? What do the timing maps look like? Fuel injector size and offsets correct? Since you have a '93 the VE tables are EXTREMELY important. I know as I have my car running in speed density The XE cams can be quite touchy when it comes to part throttle tuning. I'm assuming this problem started with the cam change? Nothing obvious mechanically wrong such as excessively loud valvetrain, bad fuel pressure, exhaust leaks, etc.?

Send me an email. I'm busy with finals coming up but maybe I can offer some suggestions when I get the time.