rs657f

Hello all i need some serious help here. About two weeks ago i think i had some bad gas in the car, car ran fine in the morning and afternoon, after fill up it went nuts. It had the heavy sputtering at idle and weak acceleration. I ended up draining the gas and changing the fuel filter. Nothing has changed, it still vibrates at idle and when slowing down under 10mph it shakes terribly. I cut the CAT off and had a fuel system cleaning this weekend and nothing changed again. I put in a new MAF and intake elbow to be on the safe side, still no changes. Yesterday I changed the fuel injectors and put in (ford denso 24#), cleaned the TB, the TPS and the IAC. Now the car does not idle lower than 1200 rpms and it does not accelerate past 10mph. It sounds like its miss firing and running rich. Before i end up throwing money away at a shop i would like your opinions and what you think i could do. I am super stressed with this. Thanks

moparman

What kind of car is it?

Any mods?

Scanned for trouble codes?

Fuel pressure been checked?

rs657f

It's a 95 z28. No mods. The acceleration is bad I can't even drive it up to the shop to get the codes tested. It does have an ses light on and the high idle. This was after cleaning all the parts on the TB. I checked the fuel prejssure it showed 0 psi when I turned the key to the on position. It was a rented guage that I think was broken so I will be buying a new one for myself to try it again

Injuneer

You can scan it for codes yourself, using free download software, specifically for the 94/95 LT1. All you need is a cable.

https://www.camaroz28.com/forums/com...95-lt1-874306/

A lot cheaper than playing parts replacement roulette.

Did the pressure gauge you rented have the pin in the connector to depress the valve core in the Schrader valve, so the pressure could reach the gauge? Did you hear the fuel pump prime for two seconds when you turned the key to "run"?

rs657f

Nice thanks, i will give that site a shot now and see how it turns out

I ended up replacing the IAC again and tightened all parts on TB. I still have the SES light on. I noticed that it idles around 1100 RPMS which is a little less than yesterday. The car also jumps a bit when shifting into gears like the gas pedal is stuck.

I also rented another fuel pressure tester today and my fuel pressure is around 30 psi when i prime the key and the pressure drops immediately. The FPR is new and the injectors were just put in. I am assuming its the fuel pump. it still smells rich and idles high, would lack of fuel cause that to happen?

Injuneer

Stock idle for an A4 is 550 rpm in gear, 650 rpm in neutral.

Lack of fuel would cause it to run lean. The PCM can correct that based on feedback from the O2 sensors. But there is a limit to how much fuel it can add.

What is the fuel pressure with the engine idling, and the vacuum line off the FPR? Should be 41 -47 psi. What is the pressure when you reconnect the vacuum line? Should drop about 8 psi from the "no vacuum" pressure.