Okay, My 97 has about 260K on it so expected to see some problems here and there... Im trying to avoid the $100 charge for the shop to run a test and not fix anything. It started a while back, when runnin hard i would miss just a little bit going into 3rd. but that was it.... then saturday, The miss got so bad i couldnt get over about 40. We put all new plugs in and found the 2 of the plugs werent even screwed in tight... so i now have the bosch platinum 4 prongs. We checked each coil pack and they all arked off the block. We replaced the fuel filter, and hollowed out the cat, (i have been throwing a cat code on my CEL along with the o2 and EVAP system) I put in a new o2 sensor last night... now its only at low RPMs when the miss happens.. anything over 1500 is fine. The evap is still throwing a code but i havent gotten to check the CEL yet since the o2 was put in to see if that code went away.
At this point the only code should be 0705 wich points to a problem with the Evaporative Emission Control System, and then lists about 30 different possible problems >
AND 0903 which indicates a problem in the evaporative Emissions Canister Vent Control Valve or its associated electric circuit... It also states this is only used for self diagnosis and the car will operate perfectly fine with this code. :/

So I am kinda at a loss.... Any ideas on what this could be????

 

Change plugs to OEM NGK

 

The only thing is I JUST bought these plugs on saturday :/ money isn't in abundace for me

 

you need to go back to where you bought those bosch plugs and ask if theyll exchange them for NGKs...if not, just get the vpowers for now....1.99 each or so.

 

Is there a problem with the ones i got or are the NGK's just that much better?

 

NGK's are the suggested ones by manufacturer

 

I guess what im thinkin is, is this gunna fix my miss? could that be the cause?

 

SEAFOAM! we had a vdubb in my buddies shop that kept coming in with a misfire, we tried everything and nothing helped. So we ran a can of seafoam through it, cleared the light and sent it off, havent seen it since!

 

Wich code did you have for the O2? A bad pre cat sensor will cause a lean or over rich miss. Bosch have been known to give a miss in the VQ. Was there any oil in your sparkplug tubes? Tube seals will occaionally leak and breakdown the spark plug boots.

 

the code was 0503 Front Right Heated O2 sensor

0503
Diagnostic Trouble Code 0503 indicates a problem with the front Oxygen Sensor on the right cylinder bank. The right bank is also called the rear bank. It is cylinders 1,3,5. A normal signal sweeps back and forth between 0.2 volts and 0.8 volts. This malfunction was detected when the Engine Control Module received a signal from the sensor which was a constant value of approximately 0.3 volts.

Possible causes include ...
- Harness or connectors (the sensor circuit is open or shorted).
- Defective Oxygen Sensor

When i pulled the old plugs, 2 or 3 werent screwed in tight... and there was oil on the coil pack tubes on those.... ???

 

so with the seafoam.... just spray in the intake? I see it basically just cleans up the motor....

 

Have you tested your injectors with a multimeter?

 

I have not.... I can probably do that tomorrow..

 

Yeah it might be a good idea to. At 170k I had the same problem. Only cylinder one was detected as misfiring and it was intermittent. Upon testing my injectors with a multimeter I found I had 3 bad ones.

 

I pray thats not it... i dont want to fork out that much money... Im hopin its just a tank of bad gas... I was 40 miles into a new tank when this started.

 

Im going to have to get to the injectors under the intake manifold arent i?

 

You can disconnect the harness connector close to the power steering resevoir and measure specific pins on that connector. I have a WORD file with pictures describing how to test those firewalled fuel injectors. I converted it to a HTML file but I couldn't upload it into my album beacuse of the images within the file.

Send me a pm with your e-mail address and I'll reply with the WORD file attached.

 

pm sent.. Thanks

 

So like I said earlier, I put in the O2 sensor about 24 hours ago now. Well on my lunch break it had acted ok going to lunch but acted up again on my way back to the office. Driving hom after a meeting tonight, it was perfectly fine. No issues at all. So I'm gunna run a few more days and see if it comes back.

 

You need to do a complete valve cover gasket set with grommets and tube saels, then replace the oiled down coil boots. replace plugs with NGK and fix your O2 sensor issue. Untill you do ALL that your pissin in the wind.

 

Whats the point of the complete valve cover set?

 

Depending on which tubes had oil on them, He's gonna at least need to do one VC. If they're both in one head he can get away with one VC gasket job. The tube seal gets old and hard and leaks oil from inside the VC into the tube. The hot oil breaks down the rubber boots and the spark leaks to the tubes. That is where he is getting the misfire. IMHO, half assing a VC gasket job is a waste of time.

Don't mess with your injectors until you fix your ignition problem.

 

Couldn't agree more^^ If you have oil in your plug tubes you're going to have a miss-fire. I bought a gasket set on ebay for $25 and if did the trick for me. the brand was Apex and it came with both cover gaskets, all new tube seals, and even some shiny new zinc plated grommets.
Also, ditch the Bosch plugs. NGK Iridiums run noticeably better in our cars.

 

bring those plugs back and say they messed up your car. they are NOT recommended. get the 2.99 or whatever they are NGK Platinums. dont any other plugs cause detonation at times?

as far as the evap goes - you wont pass emissions, your car will stink of gas at times, and your mpg will have a slight decrease.

my buddy had the same problem with the missfire and inability to drive at certain rpms. turned out to be a coil pack. he replaced them all with new ones.

p.s. make sure you torque those plugs into that aluminum

 

Ya the boschs are torqued in good this time. I made sure of that. I had a lesser experienced freind help the last time... learned my lesson there. so they are all in. Ill see if advance will take the plugs back and get the NGK probably this weekend. Im pretty sure that i also had a bad tank of gas. (not saying this was the only problem) I also want to do the 00vi so when i get that and i have the top of the motor off i was plannin on doing all new gaskets anyway so that works also.. Thank you guys for all the advice. If anything else comes to mind please let me know.