So here is where im at. Ive put new plugs, wires, distributor, and fuel filter on my 99 Y7. Ive checked valve lash, fuel pressure, and ignition timing. Got in time with distributor in the center so that tells me mechanical timing is in spec. Compression test came to be 175 across the board just cranking the motor. (did not hold throttle wide open) I did a timming belt about 3k ago. Right now the motor hesitates and misses. sometime it will throw a P1399 code. It wont do it all the time. Tonight i noticed it the most out on interstate at 70 (3k Rpm) and 40 (2-2,500,rpm) it also like to miss once or twice durring a shift and at high rpm around redline. I have no idea whats going on.
what is left to test? Tested the injectors with a noid light too. Is it possible that the crank flucuation is causing the missfire but not throwing a code for it? Maybe its causing the injector not to fire at the right time or something. THe wires for the CKF have not hit the alternator belt and I have also sea foamed and ran lucas fuel injector clearner threw the gas.

 

Aftermarket distributor?

NGK plugs (properly gapped) and OEM wires?

 

NGK gapped. denso wires but Ive tried autolite and duralast. Tried a new duralast distrib but just put my oem back on with new beck arnley cap and rotor. Coil testesd good in both.

 

Not sure what you meant here^.

Did you pull the fuel injectors and inspect them?

 

the distributor is almost dead center of the adjustment. if timing was off a tooth it would be far to one side. I have not pulled the injectors yet. Weird thing is that it did this about 2 months ago, I threw parts at it for days test driving it almost 300 miles over 3 days. Got up and drove it to school and it has been fine until yesterday.

 

Check the injectors. They may be partially clogged.

What was the fuel pressure with and without the FPR vacuum hose connected?

Does the problem go away if you unplug the primary O2 sensor?

 

Problem persist with o2 unpluged and fuel pressure was spec when i tested it. I think 36 and 46 was spec. cant remember. now whether the fuel pump is getting lazy and losing pressure when driving is another story. I dont think thats happening though.

 

How do you see if an injector is clogged? Is there a way to check the spray pattern>

 

Do the CKF bypass, takes like 2 minutes. http://technet.ff-squad.com/ckftrick.htm

 

CKF will not cause a misfire. The CKF is used for detecting a misfire.

 

New info tonight. Haven't been able to pull injectors. Buy was watching o2 voltages and as it was hesitating it ran rich until I let up off the accelerator. It went up to the top and almost was flat line. The graph had some small dips but not like normal. When it misses if you let it coast then get back in it sometimes it clears it up. Going to check injectors this weekend.

 

runs worse with o2 unpluged. got a used set of injectors and will be putting them on

 

why'd u buy more injectors? have u checked the ones installed yet??

 

They where 20 for the whole set. If i pull mine and i can clean it I will but I have a feeling that There is something inside that wont just clean out