Anyone know why my 88 tpi 350 could be surging at low acceleration? Will also die when in gear if creeping. if not warmed up.. (Apologies for the shaky video. It's like a rocking bull when it surges) seems to go away when I accelerate harder.. does not do it in park idling
update--- finally threw a code. Code 44 Oxygen sensor error (lean condition indicated)
Any ideas?
updated video of issue-
https://youtu.be/z91nhCmKml0

 

I have seen a few people with this problem and it was the tps. So I guess that is where I will start.

 

TPS or MAP/MAF will throw things off. Check them with a DVOM I'm not sure of the ranges

 

Has new TPS (set to .54) and IAC. Finally threw a code 44 today.
Ideas on what the most common issue is for a code 44?

 

Start with fuel pressure check , is the engine all stock ?
exhaust leaks on the drivers side ?


http://web.archive.org/web/202007032...vythunder.com/

 

Yes, Motor is all stock
what is the fuel pressure supposed to be?

 

Tried to find it online. Found 42 at idle and 47 at WOT does that sound right?

 

I dont think my previous video link was working. https://youtu.be/z91nhCmKml0

 

Fuel pressure at idle 32, when you see it jumpy that is when it is barely being pressed and its acting like its missing then it goes down when I reveal it past that When the FPR is disconnected its a steady 42. Is this a sign of a bad FPR?

 

Well I have searched for any vacuum leaks none found gas pressure is good. I have also replaced TPS, IAC, Fuel Filter, 02 sensor and MAF. From a short drive the issue was the MAF sensor because the rpms no longer bottom out when stopping and no more surging at light acceleration.

 

Bouncing fuel pressure gauge needle is normal on batch fire. Remember, you have all 8 injectors firing simultaneously every rotation of the crank. There is no way, measured at the rail, that pressure is going to be steady at idle speed. Your pressure is pretty normal. Do you have a scan tool? If so, use custom data to select only O2 sensor voltage. Is O2 dropping low as the engine loses power? It's possible that the O2 sensor is not responding quickly enough, allowing the system to go too lean before the O2 voltage drops to signal the ECM to increase injector pulse.
Other causes of surging would be too lean AFR. Looking at O2 voltage, is it hanging low? Look at INT(short term fuel trim) and BLM(long term fuel trim). 128 is neutral for each of these PIDs. Higher is lean, lower is rich. Are they sticking high? This would mean you have unmetered air or an air/fuel metering error causing the engine to run lean.

If the surging is caused by a sensor such as TPS, you should see the value change with the surge. Of course MAF is going to rise as the engine accelerates. Still a low MAF could cause the type of lean condition I just mentioned.