So here's some back ground. Car started out as hard to start when warm. Changed ect. Cleaned maf. Car still hard starting when warm. There are times I have to floor it to get it to go. Now today I got check engine lights. P1128 p0455 p1138 p1136.
Can a purge valve cause these? Also need to note I drive mostly hwy and I'm averaging 18 mpgs now....

 

17536/P1128/004392 - Ross-Tech Wiki

16839/P0455/001109 - Ross-Tech Wiki

P1138 - Ross-Tech Wiki

17544/P1136/004406 - Ross-Tech Wiki

All say something about system too lean or MAF.

Best/cheapest place to start is to do a smoke/vacuum test.
Could be your MAF, how did you clean it?
Could also be an O2 sensor.

 

The O2 sensors are off-line during startup, so I think you can rule that out. The next thing to is disconnect the MAF, and see if there is a sudden improvement, which would suggest the MAF isn't working correctly. However, I wouldn't be surprised if there is an air leak some place. Look for broken plastic vacuum lines or rubber hoses, split in the plastic flex duct, poor-sealing valve cover gaskets, oil cap, rubber half-moon plugs behind the heads, etc.

 

I read somewhere that disconnecting the MAF and seeing an improvement doesn't necessarily mean the MAF is bad, just that the system doesn't think one exists so it doesn't alter the air/fuel ratio.

 

I'm no MAF expert, as I understand it, the ECU needs to know the mass of air is being consumed by the engine (MAF sensor), and temperature of the coolant (CTS) to select the appropriate fuel injector pulse time. If one or the other signal is missing, the ECU substitutes a default value for it, until the O2 sensor(s) warm up enough to take over. If a signal is just plain wrong, due to a defective sensor or other circuit problem, but the signal is within the range that the ECU is programmed to accept, the engine may not start due to the fuel mixture being too lean or too rich to light.

 

I thought, if there's no signal from the MAF sensor or coolant temp sensor, it set a default value but that the value never changes, regardless of the o2 senors.
It picks a value of fuel and air that it knows is okay to drive the motor and won't kill the cats but it won't necessarily give you great gas mileage.
I may very well be wrong, but that's how I understood it.

 

Bad coolant sensor will make a 2.8L almost impossible to start, it acts like an old flooded carbureted car, and the gas pedal has to be held to floor to get it to start. Note that there are two sensor loops in a temperature sender, one for the gauge in the dash, and one for the feed to the ECU. The one to the ECU is the important one, and the one that screwes up starting the car.

 

I replaced ect behind head on passenger side. I didn't replace the identical sensor in the lower radiator hose upfront.
When I get gas now car is really hard to start. It will start and die several times.
Maybe do a fuel pressure test?
Could a stuck open thermostat cause these peoblems?