Engine stutter, hesitation at WOT
03-28-2013, 01:39 PM
#22
Gentleman's Relish
Join Date: Feb 2005
Location: AZ
Posts: 13,090
I would go in this order.
Fuel filter - it's an unknown at this point
CAI - check all connections
Check - TB and MAf although if it was progressive my money is still on the fuel filter.
Return to Stock - see if the problem goes away (doubtful though).
Fuel filter - it's an unknown at this point
CAI - check all connections
Check - TB and MAf although if it was progressive my money is still on the fuel filter.
Return to Stock - see if the problem goes away (doubtful though).
03-31-2013, 10:15 AM
#23
Update:
Replaced Fuel Filter
Cleaned TB
Cleaned MAF
Checked all connections for intake
Thought we had it isolated to Cyl 1 misfire replaced cyl 1 coil
Still happening
Drove it rough while it was happening to get it to throw a damn CEL
Got a CEL so I took it to pepboys to have them scan it.
Here are the codes and a short description;
P0452 - Evaporative Emission System Pressure sensor/Switch low
P0454 - Evaporative Emission System Pressure sensor/Switch intermittent
P0642 - Sensor Reference voltage a circuit low
P0192 - Fuel Rail Pressure Sensor a circuit low
Replaced Fuel Filter
Cleaned TB
Cleaned MAF
Checked all connections for intake
Thought we had it isolated to Cyl 1 misfire replaced cyl 1 coil
Still happening
Drove it rough while it was happening to get it to throw a damn CEL
Got a CEL so I took it to pepboys to have them scan it.
Here are the codes and a short description;
P0452 - Evaporative Emission System Pressure sensor/Switch low
P0454 - Evaporative Emission System Pressure sensor/Switch intermittent
P0642 - Sensor Reference voltage a circuit low
P0192 - Fuel Rail Pressure Sensor a circuit low
04-01-2013, 06:34 AM
#25
2nd Gear Member
Join Date: Aug 2009
Location: Somewhere in southern Indiana
Posts: 178
He needs to chase that p0642. If the sensor reference voltage is low (below 5 volts) he will have all kinds of funky problems. Either the altenator is going, loose wiring, bad ground or the pcm is starting to go. That P0642 will cause all of his other codes.
04-01-2013, 10:34 AM
#27
Yeah this is getting very frustrating for me. Upon further research I thought maybe resetting my ECU would help. So yesterday I disconnected the Negative battery cable for about 45 minutes. Reconnected it and let it Idle till it was at normal temp. Then I turned on all my accessories including the AC and let it idle for 5 minutes. Took it out driving and the problem was still present. Someone else posted on this thread that they replaced their alternator and that fixed the issue. Do you think that could really be the case?
04-01-2013, 10:44 AM
#28
2nd Gear Member
Join Date: Aug 2009
Location: Somewhere in southern Indiana
Posts: 178
With the key on and the engine off, unplug your fuel rail pressure sensor. Check between the brown wire with a white stipe and ground with a volt meter. You should have 5.0 volts at that wire. 4.98 -.99 is ok, but less than that you have a problem. After you check that , also check your battery voltage with the engine not running, and then running. You should have about 12.5 volts not running, and about 14.3 - 14.6 running. Anything outside of these numbers, is where you should start to look.
04-02-2013, 08:34 AM
#30
So another update...Went to the shop and tested it again. They still think its a misfire. So we went driving while we had the computer hooked up. I was reading the scanner while he was driving. Not a misfire problem. None of the cylinders showed any spikes while it was acting up so it has to be fuel related. He was going to check the fuel pressure at the rail but as far as we can tell the S197s don't have a fuel pressure test port! So we have to order a special adapter to test the pressure. I wont know any more till later this week.