Car doesnt accelerate as fast anymore

BlackZMamba

Ok so I am assuming OP is going into Limp Mode. It was happening to me after I installed the Long Tube Intakes. Small particles or things like bugs can get into your Mass Air Flow Sensors and damage the small filaments inside the air flow sensors. It is recommended that you clean both sensors really good and re-install. Cleaning the throttle bodies is also a great idea. I personally had the same issue as OP and did this and the issue went away. I agree with everyone else commenting the same suggestion.

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Khanxyz0z

https://ibb.co/c2LLFo

The link has the photo of the codes.

So after this i bought 2 mass air flow sensors from someone on ebay from a crashed Z.
i deleted the check engine and it came back after 150 miles.
do i need to reset the ECU entirely?

Jhill

Ok so now you actually have codes to work off of. P0171 and p0174 so both banks are lean not just one. So things that are shared would be something to start looking at. What is fuel pressure and volumn values? Any vacuum leaks? PVC check valves. You have basically eliminated the MAFs (it's unlikely you got two more bad MAFs). So look for reasons why the car would be lean (unmetered air or can't deliver fuel demands) that would effect both banks, exhaust leaks before cats could be a cause but again the odds of having two is less common than something both banks share same for AF sensors. Now you actually need diagnostics.

Khanxyz0z

So rechecked, and the code now is
P2099
Feel like selling the car now, who knows what mew code will come up if i fix this.

B&W_Evader

Looks like fuel and air issues to me. I have a cheapo 15$ reader and I can watch the voltages on all the sensors. Had it for a while now and works pretty good. Plug it in and rev the engine a couple of times. You should see stuff voltages changing. The internet can explain each item if you search on it.
Software icon says "OBDwiz". Just plug the adapter from the car's OBDII port to my laptop USB. Helped me isolate my check engine on my Tacoma to the O2 sensor. Fixed on first part replaced.
Checked a code on my Z the other day. Cyl 4 misfire. Reset and it's been good. Think that one was a bad tank of gas.

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|RIP|6spd-sport|OSG-LSD|XP8|RBF600|Eibach Sways|RE-71R|FI-34Row|Gen3-CAI|Yaw P.S.|

Jhill

Honestly these are very reliable cars and fuel trim codes shouldnt be hard for a competent tech to diagnose. If you don’t have vehicle knowledge then it is time to stay clear of the autozones, free scan diag shops etc. all they will be doing is getting the code and throwing parts at it, which you have already done yourself. Time to take it to a real shop, maybe one that is gold shield certified for emissions repairs (not sure if that applies in your area) as these are the shops that have to actually fix cars once all the parts changers are done and throw their hands up.

Good luck, as I said it shouldn’t be hard for a competent tech to diagnose fuel trim issues but sadly those are getting harder and harder to find as the industry keeps pushing them out. Once you find one keep him, possibly even his personal number if he isnt the shop owner, in case he quits. All the shops and dealers seem to forget it’s the techs that make the shop/dealer not the other way around and they only recognize it after people start quitting and their reviews tank.

B&W_Evader

My guess would be intermittent vacuum leak. You've got codes upstream and downstream of the engine all related to fuel/air mixture. Check for a loose or cut hose around the intakes. I think it's unlikely the gaskets are leaking unless you've had the manifolds off or have overheated the engine. If you run rich you can burn out the cats. Then you'll really loose power as the air won't flow through them any more. If all else fails, may want to consider a compression check on each cylinder to make sure it's not something really bad.

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|RIP|6spd-sport|OSG-LSD|XP8|RBF600|Eibach Sways|RE-71R|FI-34Row|Gen3-CAI|Yaw P.S.|