Engine Slight miss/surge at light throttle cruise

Tufgriz

New Member
Sep 23, 2019
23
0
1
Washington
My old combo ran great no issues except engine was tired and smoke explorer intake tsf 1 cam gt40p heads 24lb injectors c&l mass air with 70mm tb msd 6a with msd coil. Changed engines and went to a lunati cam with simalar specs to the trickflow, trickflow track heat intake, brodix st 5.0 heads. Rest of the combo was the same. Now during crusing around 1700 rpm I have a slight stutter or miss that is acting like lean stutter or a tad bit to much timing. I have retarted timming and it didnt to much except except make the car lazy. The only thing that has seemed to help at all was forcing the car to stay in open loop. Base timming is at 12 with spout out and fuel pressure is around 37 pounds vaccum line off. Does anyone maybe have some ideas i may have missed? I have also searched for vaccum leaks and have reinstalled the intake and no change. If I apply just a slight throttle it will clean right up and be fine its just when I try and maintain a steady rpm or speed. Im just trying to come up with some ideas to check that I may have overlooked thanks
 
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Dump codes sticky

Look at the top of the 5.0 Tech forum where the sticky threads are posted. One of them is how to dump the computer codes. Codes may be present even if the CEL (Check Engine Light) isn’t on. You don’t need a code reader or scanner – all you need is a paper clip, or if your lady friend has a hair pin, that will do the job.
I highly suggest that you read it and follow the instructions to dump the codes. http://www.stangnet.com/mustang-forums/threads/how-to-pull-codes-from-eec4.889006/
 
Ive deleted egr about 5 years ago and on koeo. Ive got 67 81 82 and 84 on memory ive got 29 32 41and 91. The 02 sensors are most likely from when i ran it after unhooking them before i changed them and drove it at which tine it acted better when in open loop. Havent got any of the engine running yet and plan to clear all codes soon when i reset my idle
 
The ECU is expecting the car to recirculate the EGR gasses and when it commands the charcoal canister purge valve the ecu should pull fuel out [it is now getting fuel in the form of fumes from the canister]
 
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Do not mistake my above comment for all conditions... this is only in the low load cells where the flame front is moving very slowly.

you will quickly destroy an engine doing this under any kind of heavy load [read acceleration]
 
I will get the cannister line hooked back up. I believe it was unhooked before the engine swap but cant remember for sure. Clutch switch should be in tomorrow but if i get a chance today I will run it around some after hooking the line back up (hunting today)
 
so, thought this may be interesting. While waiting on the clutch switch tomorrow I messed around under the car to check out the code 29 vss. apparently the previous owner had stripped the wires bare and had them connected together so I fixed them and reconnected the sensor. upon firing it back up immediately the idle jumped to aroun 1500 and was popping and sputtering and missing really bad. attempted to move the car around and it continued would not idle down at all. So shut it down and attempted to pull codes again, the computer would not respond at all. disconnected the vss and tried again and still the computer would not respond so I reconnected the two wires together again and bam the computer dumped the codes and threw a bunch of differnet ones
KOEO 67 81 82 84 95
memory 22 34 51 53 54 63 95
I tried firing the car back up with the two wire connected after pulling codes and the car ran just like normal