Thought it was fixed! Damn light just came on again. If I had hair, I'd be pulling it out about now.

 

have someone look at the car that know how to use a good scan tool

 

My car says "check gas cap" on the DIC when I get a p0455...you need to know what code you are getting.

Might I suggest you check the hard plastic line that goes along the drivers side head back to the firewall where it plugs into another device of some sort. That hard plastic line might have gotten pinched or removed from the devide by the fire wall during the installation.

 

I bought and replaced that hard plastic line.
I don't know of any good mechanics around here. Dealers are worthless.

 

As previously posted, go to Wal Mart and get an scan tool - they are about $69 (get one that can do CAN networks, most can today) and let us know what the exact code is. That'll help and the scanner is very useful.

For example, recently my car started running like crap at idle and it was adding +25 fuel trims at idle...driving around was ok...it was so lean that it would hardly run until it got good and warmed up.

Turns out I was getting a MAP sensor low performance code, and I took it out, and sure enough, it was coated with oil. I cleaned it with MAF (the F is on purpose) cleaner and the car is running a lot better.

I've ordered a new MAP sensor and I'm going to rig up a PCV oil catch can system before I install it. I'm getting a fair amount of oil in my intake and now with the FAST, where the MAP is, the sensor can get a lot more oil in it than it did on the top on the factory intake.

 

Did you disconnect the battery and let everything reset? I thought I was going to have to do that with mine but after a few times driving the car the ecm recognized the new gas cap and the dic never brought up the message again.

 

ok, thanks

 

I did dis-connect the battery for about an hour. Drove it around for 2 days with no DIC message

 

do you have the factory repair manuals for this car

 

Po455

 

again find someone with at least a snapon mtg2500 then perform an EVAP test and the required tests for that code following the diagnostic tree

 

EI07238 — Fuel Cap May Not Seal, MIL/SES Light Illuminated with DTC P0442–Evaporative Emission (EVAP) System Small Leak Detected and/or P0455– Evaporative Emission (EVAP) System Large Leak Detected
Models: 2005 Buick Rainier
2005 Cadillac STS
2005–2006 Cadillac XLR, XLR-V
2004 Chevrolet Express
2005–2006 Chevrolet Corvette
2005 Chevrolet TrailBlazer, TrailBlazer EXT
2004 GMC Savana
2005 GMC Envoy, Envoy XL, Envoy XUV
2004–2005 Pontiac GTO
2004 Saturn ION
2004–2005 Saturn VUE
with 2.0L, 2.2L, 2.3L, 2.8L, 3.5L, 4.2L, 4.4L, 4.6L, 4.8L, 5.7L, 6.0L or 7.0L Engine
(VINs 4, A, D, E, F, G, S, U, V — RPOs LJ3, LC3, L61, LK9, LP9, L66, LH2, LL8, LR4, LS1, LS2, LS7)

Attention: Proceed with this bulletin ONLY if the customer has commented about this concern AND the EI number is listed in GMVIS. If the customer has not commented about this condition or the EI does not show in GMVIS, disregard the bulletin and proceed with diagnostics found in the published Service Information.
THIS IS NOT A RECALL—refer to Service Bulletin 04-00-89-053A for more detail on the use of Engineering Information Bulletins.
________________________________________ ____________________________________
This bulletin is being revised to add additional models and model years and new contact information. Please discard Corporate Bulletin Number 07-06-04-022A (Section 06 — Engine/Propulsion System)
________________________________________ ___________________________________
Condition
Some customers may comment on a Service Engine Soon (SES) Light illuminated on the IP cluster and the fuel cap does not seal or tighten. Technicians may find DTC P0442 and/or P0455 set.

What Action to Take
GM Engineering is attempting to determine the root cause for fuel caps not sealing and/or setting codes P0442 or P0455. GM Engineering has a need to obtain information first hand from the dealer technician during diagnosis and before repair. As a result, this information will be used by engineering to "root cause" the customer's concern and develop/validate a field fix. Please follow the instructions below regarding the requested information.

Instructions
Important: If a vehicle is encountered with the above concern, complete the following steps; making sure all the information is documented on the Repair
Order.

1. Verify that the VIN and mileage is accurate.
2. Accurately document the customers concern. If the SES light is illuminated, record the Diagnostic Trouble Codes (DTC) using a Tech 2®.
• If DTC P0442 - Evaporative Emission (EVAP) System Small Leak Detected is stored, proceed to diagnosis DTC P0442 in SI.
• If DTC P0455 - Evaporative Emission (EVAP) System Large Leak Detected is stored, proceed to diagnosis DTC P0455 in SI.
• If diagnostics lead to repair other components not related to the fuel tank filler pipe neck or fuel cap, repair accordingly and disregard this bulletin.
3. If the diagnostics lead to a leak at the fuel tank filler pipe neck or the fuel cap area, inspect for the following conditions:
• Inspect the condition of the fuel cap by looking for small cracks or any damaged components.
• Inspect the fuel cap seal for distortion or cuts.
• Inspect the fuel filler neck sealing surface for gouges or dents produced accidentally by a fuel nozzle.
4. Contact the appropriate GM Engineer once the vehicle has been diagnosed and before repairing the vehicle for further instructions.
Engineer Contact Information

Contact the appropriate GM Engineer from the list below before repairing the vehicle. GM Engineer Shannon Fahy may be used as a secondary contact. GM Engineering may visit dealerships near the Southwest Michigan area. In either case, you will receive a response back within 2 hours on what action to take the same day of your call (Eastern Daylight Time).

Warranty Information

Important: DO NOT use the labor operation listed below if engineering did not respond.

For vehicles repaired under engineering direction, use: Labor Operation Description Labor Time
L9714* Engineering Information-Fuel Cap and Filler Pipe – Replace
Corvette/XLR 1.8 hrs
Express/Savana 0.8 hr
GTO 0.7 hr
Envoy/Rainier/ TrailBlazer/VUE 1.0 hr
STS/ION 1.4 hrs
*This labor operation number is for bulletin use only. This number will not be published in the Labor Time Guide.




Also, check your hoses and inspect yours-you may find they are cracked, split, etc. Leakage throws the same code as a leaky, or not tight, gas cap.

 

Same thing happened to me yesterday. I had a spinfast modded manifold professionally installed and on the way home I got a " check gas cap" message on the DIC..Did your check engine light also come on? I'll try a new cap this week, but after everything you've said I'm not convinced that a new cap will solve the problem. I'm also wondering if the car will pass NY state emissons with this condition.. Performance wise the car runs like a raped ape with the modded fast.

 

Is there anything you forgot to plug, the line at the rear of the manifold pass side??
the map sensor up front??the valley to the intake???

 

I had the same problem after my FAST intake was installed. Yesterday one of the great mechanics at MSI (N. Calif Corvette shop) discovered that some FAST intakes must have been manufactured with a blockage in their evaporation ports, this port is located on the left side of the intake and just behind the throttle body. This is what the hard plastic evaporation line connects to.
The problem here is that the evap line flowed into the blocked port, my code reader validated this because not only did it read P0455 it also stated no flow. To fix this a small drill bit will be needed, insert the drill bit into the evaporation port and extract plastic blockage, now if you guys try this you must make sure to completely remove the blockage or old P0455 will resurface again. I've driven over 200 miles since yesterday and so far I'm enjoying nothing but a ton of drama free horsepower. Give it a shot guys and I'm sure this will cure the FAST PO 455 (GAS CAP) blues.

 

After receiving a PM on the problem from QuickAg, I went and checked Buddy A's manifold which he sent to me to check out. As some are aware, Buddy prepped his own manifold and did a pretty good job of it. He didnt port the plenum and the area where the plugged opening is was never touched. I tried to blow air in it and it was in fact blocked.

Having 4 other FASTs waiting to be prepped, I opened all four cartons and 3 were blocked in the same way new in the box. I drilled out all of the affected manifolds and if anyone else gets this code they will need to remove the TB and remove the plastic VAC line going into the front driver's side of the intake plenum. Use a rag to catch any plastic filings as you drill the opening to unblock it.

The fix is a few minutes to take care of.

Any manifolds from me will have already been checked from this point on.

 

Son of a gun. Well I'll check mine, but I'll bet it's plugged as I'm continuing to get the PO455 code.

Nice work Quick AG!!

 

A big thanks to both Quick Ag and Spin (Guy). This forum is great.

 

thanks for the report

 

Guy I haven't had a chance to pull my throttle body off to look at this, but when the car is idling, that port definitely pulls vacuum so the port is at least somewhat open. If I stick a drill bit in the port, it stops about 3" in however.

Is that port supposed to be completely open clean through to the plenum? Are the ones you are seeing blocked completely blocked are or they partially blocked? I can take the throttle body off again and drill it out but thought I'd ask first.