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Fuel Issues...?

GP40TH

GP40TH

New member
Hey guys. I think I am having issues with my L67's fuel system and cannot find the solution. At first, the engine would start spitting at around 4k when accelerating and I would loose power. What's strange is that the severity of the issue changes every time I drive the car, but during every drive the severity is usually consistent. No misfire codes. No check engine light even, but fuel economy is noticeably low. So far, I have replaced the fuel regulator because the pressure was bouncing around, most of the vacuum lines under the hood, cleaned the MAF, and cleaned the injectors. Fuel pressure seems good (~40-50 psi) at any RPM when the car is stationary. I have a new fuel filter to install but the old one is rusted to the line fitting pretty well. Other than that, does anyone have any ideas about what the issue could be?
 


*UPDATE*
The new fuel filter has been installed and the issue has not been resolved. Idk what to do next. Maybe the injectors are failing???:(
 
What's the trick? Pressure sits around 42psi idle and fluctuates between 50-60 under load. Under heavy load when it starts spitting, it rapidly bounces between 50 and 60 psi. Needle bounces 1-2 psi at idle but levels out as RPMs go up. Also, the MAF and MAP seem to read fine.
 
Someone mentioned to me that it could be the crank position sensor. There aren't any codes for it, but any thoughts?
 


the crank wont throw any codes the only way you will know is if your tac bounces when you crank it. but since it fires im guessing its fine
 
ericspecullaas said:
what is your fuel pressure at? also have you tried the trick with the fuel pump relay to make it run fast?
Click to expand...
fuel pump relay thing only applies to 97-00 gtp
Crank sensor bad is usually a stalling issue, possibly a clogged converter if it's losing power at that rpm
 
The power is down only when it starts missing, causing a jerking feeling. Wouldn't the cat cause more of a constant power reduction?
 


Plugs and wires were done around 40k ago. Fuel filter was just done and the injectors were just cleaned. Just replaced my 3 year old cone filter. Lower intake gaskets were done about 25k ago and everything was cleaned.
 


it could be the plugs are just getting old, or the cat is clogged up. maybe pull the up stream o2 sensor and see if it runs better, your making a good exhaust leak pre cat.
 
Okay, I fixed the issue! I pulled the plugs just to see how they looked, and they were fine, but I replaced them anyway. Also pulled the upstream O2 sensor as Scottydoggs suggested and it ran great! Put the old O2 in just to see if the plugs fixed it and the issue came back. THEN I bought a new O2 sensor and threw that in. Boom, problem solved. In addition, the MAF decided to also take a **** today, so that could have also been contributing to the issues I was having. All is well now though. Thanks for all the help everyone.
 
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