Okay im stumped on this one. This truck runs absolutely amazing until full throttle. In first and second gear right around 4500+ at full throttle it will pop and miss and not shift till i let off. I played with the throttle valve cable. Adjusted it checked all return springs. Other than that truck runs and shifts like a dream. A while back i tested fuel but it held a steady 49-50psi. Tranny was rebuilt about 50,000 miles ago it has a transgo shift kit and also a hyprtech programmer... Any ideas? Im leaning towards a tranny issue...

 

Also NO CEL!!!

 

pop and miss as in spark knock?

Better fuel and cooler plugs help.

Also, your Transgo changes the equation related to WOT acceleration and shifting. Re-read the specs provided with the kit for clarification.

Add to that the Hypertech's changes to shift points, lockouts, etc.

Many variables all at once.

You could just keep your foot out of it too. 4500 is a LOT really and shouldn't be an everyday, much less weekly seen situation for a DD.

IndyDurango

 

If you put the selector in 1st gear at half throttle it will buzz to 5500rom and not miss a single beat... Only under WOT does it do this. Truck has no spark knock. I tow my racecar all the time it never spark knocks. I run 93 octane and 180 tstat because of hypertech. And the hypertech does not change shift points. We have hydraulic trannys.. Im leaning towards a governor pressure sensor i think..

 

Clean the Throttle Body first, if that doen't fix it the issue could be an O2 sensor if it is poping out of the throttle body. Other issue could be a TPS or even spark plugs.

I do not suggest going WOT at 4500 RPM tho, you will be looking for a new motor doing stuff like that......LOL

 

Just put a brand new 52mm holley on it with new tps. Doesnt act any diffrent then when it had old TB and old TPS. Doesnt the computer only use o2 under closed loop. I know full throttle is an open loop. The plugs are autolite iridium about a year old. The truck literally runs like a dream just that popping and backfire at WOT at high rpm.

 

Well where is it popping from, the exhaust or the Throttle Body?

 

The coil wire was shorting out. Put new plug wires in it now it just sputters no popping like its not getting enough fuel.
Fuel pressure: not running-44psi
Running-idle-fluctuates between 45-48
WOT- same 45-48psi
This truck does have 250,000 miles ive had the truck for 100,000 miles and have not put a pump in it.

 

1998-1999 Durango

SYSTEM PRESSURE
All Engines: 339 kPa 6 34 kPa (49.2 psi "+/- 5 psi")

This is at idle, at full operational temp. Your readings seem low to me, I like to see them up like 50. I just did mine and it was 49.5 flat on everything.

 

Just put a new delphi fuel pump in this morning and the problem still persists. I can hear whining noise undee the hood. Think it could be injectors?