I was think my trans is on the blink But I'm getting a engine light on with the mifire feeling just cruising down the road at 55mph and at 2500rpm.Pulled the codes and I'm getting 43 which I looked and it fuel delivery.I have replaced,coil, plugs,cap,rotor wires,O2 sensor,the distubuter and cap,fuel filter,TPS ,fuel pressure regulator,air filter replace with K&N cleaned the egr valve,the egr runner ports,the IAC,FITV,cleaned the throttle body.When its cold it doesnt have that misfire or sputter feeling,only does this when it get hot.And does it only in the highest gear when the convertor is in cruise mode.I thought of many things that it may be the first is a partially clogged cat convertor,fuel pump,fuel injectors,or some kind of resistor getting hot causing this.I have been throwing parts at this thing and it has gotten costly.Also the fuel mileage is terrible

 

so if you have a code for fuel delivery why the hell are you replacing everything besides the fuel components???? Have you checked and monitored fuel pressure to see if you have consistent fuel pressure for higher rpm?

 

No I haven't done that yet.I have never done that before I'm kinda lost in that area of testing fuel pressure

 

You should start there. You should have a fuel pressure test port on the top of the fuel rail. I used a fuel pressure gauge and an adapter from a harbor freight compression testing kit due to the odd sizing of the threads m12X1.25 Someone else may be able to point you in a better direction tho. Once you have the gauge hooked up you can start the car make sure its not leaking etc. Then look for the fuel pressure regulator, its the only other circular device on the fuel rail with a vacuum tube connected and a drain hose. While at idle with that top vacuum hose connected you should be reading between 30-37psi and when you disconnect it you should be around 38-46psi. if you aren't your fuel pump may be failing, allowing too much fuel to drain back too quickly or just not running at the correct psi due to age.

 

Code 43 can also be a problem with the oxygen sensor circuit.

http://www.justanswer.com/uploads/ho...rd_code_43.pdf

 

hmm so going with what tech8 is saying, were into a combustion issue, air, fuel, exhaust. Shouldnt be impossible to figure out

 

I done replaced the o2 sensor

 

That could explain why I'm get and exhaust gas smell.

 

Ok I borrowed a fuel pressure tester and some help .at a idle with vac hose hook on regulator the reading was 29 psi.with the vac line unplugged from regulator the reading was 35 psi. So I'm leaning toward a fuel pump.please correct me of I'm wrong

 

you're correct, or the fuel filter. I dont think it's a fuel pressure regulator issue

 

I was wondering it the motor mounts would cause this misfire feeling?

 

your fuel pressure isnt correct so you will experience misfiring or rumbling.

 

If fuel pressure is insufficient then a lean misfire may occur from lack of fuel pressure to create the appropriate spray pattern and volume. It also could be the fuel is puddling, due to bad spray pattern, causing the engine to load up as well. Fix the fuel pressure issue first.

Verify voltage at the main relay for the fuel pump is full battery voltage, and check again at the fuel pump connector under the back seat.

Artificially raise the pressure by impeding fuel flow at the fuel return soft line after the FPR. If pressure raises to within spec easily without cutting off the fuel flow completely then the FPR may have a weak spring and not maintaining correct pressure at the rail. A weak fuel pump will most likely not be able to maintain pressure due to either worn components or incorrect voltage.

 

Unplug the vacuum hose going to the fpr with the engine idling from the side that is connected to the intake manifold side and smell it for fuel.

It should NOT smell like fuel.

 

had the same issue, and after a lot reading, cleaning, changing etc. turned out the be the injectors. i just cleaned them and voila.

 

I'm been thinking about taking the injectors out and cleaning them to.I done replaced the fuel filter,I'm going to clean the injectors,replace the coolant temp sensor,and replace the fuel pump since the fuel pressure is low and doesnt meet specs,and hope the skip,jerk,or misfire feeling in high gear stops and fuel mileage gets better

 

Pull four injectors from the junkyard. If that doesnt fix it, take em back and pull an ecu.

I would be curious if one spark plug looks different than the other three, which could indicate a bad injector.

 

I think I will try the ecu as my last option if everything else don't work

 

I was thinking why car only does this misfire feeling after it changes gears and just cruising at 2500 rpms at 55mph.looks like it would do it at a idle and in the other gears

 

Are you still getting code 43?
Using a voltmeter, back probe the O2 sensor wiring at the ECU and go for a drive, monitor the O2 switching.
Verify there are no exhaust leaks before the O2, nor any leaks soon after the O2.
If no code.
Might want to check your EGR feed port, EGR valve, EGR manifold main runner, and EGR ports into intake runners. Possibly a chunk of carbon moved and is now blocking flow.

Run through the basics again.
Fuel pressure, spark, check plugs/wires/cap/rotor, compression check, good reference voltage at MAP and TPS sensors. IAT sensor within range, thermo sensor within range, etc etc.

 

No I am not getting any fault codes

 

Today I replaced the main fuel pump relay and ecu.It ran great until it got good and hot then back to the misfire feeling.What's so strange is the rpm gauge don't show the different rpm.I guess I will try the engine coolant sensor next then injectors then fuel pump

 

It only does the misfire feeling after it warmed up to operating temp

 

mine did the same, cleaned injectors and missfire was gone.

 

What did you use to clean your injectors?