ICE valve (ithink that was it) and mass airflow sensor didnt work

Year make model???? A rich running engine can be caused by
Defective/stuck EGR valve
Defective/sticky fuel injector
Leaky (internal) fuel pressure regulator
Map sensor
Coolant sensor
Mass Airflow sensor
O2 sensor stuck lean (giving false reading)
Bad computer
Have the vehicles operating parameters scanned to monitor sensor operation and values to determine what may be causing this rich condition before throwing your money at unnecessary parts replacement

Remember, they don't hire rocket scientists at Auto Zone, ask your local dealership for the right part and then purchase the part at another auto store.

mass airflow sensors don't have a vacuum line, you sure you don't mean the EGR valve? if it was the regulator i doubt it would run good or make much of a difference unplugging the vacuum line, take a reading of the fuel pressure, if it starts to drop while the van is running you have a bad regulator.

try cleaning the mass airflow sensor, and change the PCV valve. I would replace the PCV valve first cause that could cause it and its a cheap and easy fix, could be stuck and gunked up or clogged and barely any air is moving into the intake, if you clean the mass airflow sensor be careful not to touch the element and not to drop it handle with care it's expensive and is a fragile part, and use mass airflow spray cleaner only. Try that see if it fix's the problem if not I would check your vacuum lines particularity the ones going in and out of the intake from the pcv valve and the one going from the airbox to the engine, then check if any of the other small lines from your EGR are all connected and not cracked broke or damaged

Description
Engine stops unexpectedly at beginning of acceleration or during acceleration
Engine stops unexpectedly while cruising
Engine speed fluctuates during acceleration or while cruising
Engine misses during acceleration or cruising
Vehicle bucks or jerks during acceleration, while cruising, or upon deceleration
Momentary pause at the beginning of acceleration or during acceleration
Momentary minor irregularity in engine output


Possible Causes
Air leakage from intake-air system parts
Improper operation of idle air control valve
Crankshaft sensor circuit malfunction
Camshaft sensor circuit malfunction
Spark leakage from ignition coil
PCV valve malfunction
Restriction in exhaust system
Open or short circuit in fuel pump and related harness
Improper fuel pressure
Fuel leakage from injector
Improper A/C system operation
Purge solenoid valve malfunction
EGR valve malfunction
EGR solenoid malfunction
Low engine compression
Vacuum leakage
Fuel pump control relay and resistor
Poor fuel quality
Air filter restriction
Electrical connector disconnection
No battery power supply to ECU or poor ground
Fuel pump mechanical malfunction
Clogged injector


Diagnostic Procedure

1. Verify vacuum hose connections, check the air filter, check for leakage or restriction of the intake-air system, ensure proper sealing of intake manifold and components attached (e.g. EGR, IAC), examine ignition components, fuel quality, and electrical connections. Are all items okay?

Yes - Go to next step
No - Service as required.
2. Check for stored OBD-II error codes. Are there any stored codes?

Yes - Go to appropriate DTC test
No - Go to next step
3. Is engine overheating?

Yes - Go to Symptom #10 for "engine overheats"
No - Go to next step
4. Connect an OBD-II scan tool capable of logging sensor output and drive the vehicle. Are engine speed (RPM), mass-airflow (MAF), throttle position (TP), and vehicle speed (VSS) PIDs within specifications?

Yes - Go to next step
No - Inspect crankshaft position sensor (RPM) circuit, mass airflow sensor (MAF) circuit, throttle position sensor (TP) circuit, and vehicle speed sensor (VSS) circuit.
5. Visually inspect the crankshaft position sensor and the teeth on the crankshaft pulley. Are these components okay?

Yes - Go to next step
No - Service as required
6. Measure the gap between the crankshaft position sensor and the teeth of the crankshaft pulley (specification: 0.5-1.5mm). Is the gap within specification?

Yes - Go to next step
No - Adjust crankshaft position sensor
7. Check spark plug condition. Are spark plugs wet, grayish white, or covered with carbon soot?

Yes - If wet or sooty, check for leaky fuel injector
No - Install spark plugs on original cylinders then go to next step
8. Remove PCV valve and shake PCV valve. Does the valve rattle?

Yes - Go to next step
No - Replace PCV valve
9. Verify that the throttle lever is resting on the throttle valve stop screw and/or throttle valve orifice plug. Are there any faults present?

Yes - adjust as necessary
No - Go to next step
10. Is there an exhaust restriction?

Yes - Inspect exhaust system
No - Go to next step
11. Check fuel pressure between fuel filter and fuel rail. Connect a jumper wire between the F/P terminal at the engine bay DLC connector and ground. Is the fuel line pressure within specification (280-330kPa or 41-48psi) with the ignition switch on?

Yes - Go to next step
No - If there is no or low pressure, check the fuel pump circuit, control relay and resistor, fuel pump relief valve as well as for fuel leakage inside the fuel pressure regulator and for a restricted main fuel line. If the fuel pressure is too high, check the fuel pressure regulator, the fuel pump control relay and resistor, and for a clogged fuel return line
12. Does fuel pressure increase when the accelerator is depressed?

Yes - Go to next step
No - Examine the fuel pressure regulator control (PRC) solenoid
13. Skip to the next step if the symptom occurs with or without the A/C running. If symptom occurs only with A/C operation, connect a pressure gauge to the A/C line and measure both low and high side pressures. Are the pressures within specifications?

Yes - Go to next step
No - Check the refrigerant charging amount, A/C pressure switch operation, condenser fan operation, and the A/C relay
14. Skip to the next step if the symptom occurs with or without cruise control operation. If symptom occurs only during cruise control operation, inspect the cruise control system. Is cruise control system operating properly?

Yes - Go to next step
No - Repair cruise control system
15. Is the evaporative emissions purge control system okay?

Yes - Go to next step
No - Check if purge control solenoid sticks open mechanically. Inspect the evaporative emissions control system.
16. Visually inspect the camshaft pulley, is the camshaft pulley okay?

Yes - Go to next step
No - Replace camshaft pulley
17. With the engine idling, disconnect the vacuum hose from the EGR valve and plug it. Is the engine condition improved?

Yes - Check for a stuck EGR solenoid vacuum valve, vent valve, and solenoid valve connector terminals
No - Check if the EGR valve moves smoothly. If yes, go to next step. If no, replace the EGR valve
18. Is the air-bypass valve actuator okay?

Yes - Go to next step
No - Replace air-bypass valve actuator
19. Check engine compression with a cylinder compression test tool. Is the engine compression within specifications?

Yes - Verify valve timing and transmission operation
No - Check for cause
20. Verify test results

DTC P1512 - VARIABLE TUMBLE CONTROL SYSTEM (VTCS), STUCK CLOSED
The air intake hose that goes from the air filter/mass airflow sensor to the throttle body they are common to crack. This air leak can cause a lean condition if that checks out ok then the issue is usually a faulty mass air flow sensor .This would need to be checked next.

Usually the actuator valve is stuck closed. These are the most common causes of the P1512 and possible causes are:
* ECT sensor malfunction.
* MAF sensor malfunction.
* IAT sensor malfunction.
* EGR boost sensor malfunction
* TP sensor malfunction.
* CKP sensor malfunction
* VTCS solenoid valve malfunction.
* VTCS shutter valve stuck closed.
* VTCS shutter valve actuator stuck closed.
* Short circuit between PCM and VCTS solenoid valve.
* PCM malfunction.

I would start with the mass air flow sensor this can cause all these issues. Then the cat. This would be the next step.

I hope this helped (remember to rate and comment this answer).

Dirty fuel injectors.

Check fuel lines for debris and if that does not fix it flush the fuel tank and pump

If you mean it starts and dies, starts and dies, the Mass air flow sensor is no good. If they replaced that, they should replace it again.

To me if the engine will not idel and stall once you have stopped, that points to an IAC (Idle Air Control sensor) which is located on your throttle body.  The part is very easy to get to and changes out pretty quickly.  Hope this helps.  Thanks for an honest rating and for using FixYa!