Hi all, need some help with this one.
Replaced in tank fuel pump, FPR, Timing, Waterpump, cap/rotor/wires/plugs. It ran awesome for a few weeks, now it has low idle won't rev up goes to about 2-2.5k and stays there more gas will make more noise, sound like it's bogging down so I replaced the main fuel pump (was really noisy) and no change. Checked pressure at inlet of fuel rail 95-100psi. Checked the MAF pins 6,7 reads 4.2ohms. Tried a different MAF from a junkyard and it was worse. If I unplug the original MAF the engine running gets worse a bit it stalls sometimes.
Checked the Idle bypass valve and that's working good, compression is 155-160 across all 4cyl. Removed all fuel injectors and visually monitored the pattern and all work normal. When pinching the fuel return line the car dies, floods it. Don't know where to go next.

Another thing is, the plugs look good not black or anything. Also I forgot to mention the car gets really hot fast like it runs lean and it starts overheating.
Any ideas? Thank you

 

Sounds like it could be obstructed exhaust, bad cat, or O2 sensor.

 

The line pressure should be 35 psi.

 

It's possible that the cat is clogged, I was thinking the same thing. When I put my hand on the exhaust it has good pressure but the running of the engine doesn't change.

I didn't have the pressure gauge inline, I just put the gauge directly on the supply line to see what the reading is therefore it read 95-100psi.

There shouldn't be much else is there? It fires up every time just fine but idle's bad and won't rev up. Almost sounds like the timing is off but I double checked and everything is on time.

 

Check your timing belt, if it's stretched and/or has slipped it can cause similar symptoms.

 

Sounds like you've done some good troubleshooting. The problem is I don't know how to check for excessive backpressure (obstructed exhaust) without pulling off the cat. I had the same symptoms you describe and it was a bad cat.

 

Usually the exhaust shop can test the backpressure they remove the O2 and use a pressure gauge in there and if I recall it shoudn't be more then 3-4psi or less but I don't have the gauge and can't drive it either.
I'll probably just cut the cat off and well a straight pipe for now just to test it. Thank you...I'll report back with the results.

 

Bingo, it was a plugged catalytic converter. removed the 3 flange screws and engine runs awesome. Thank you