gworroll

Having trouble with my 1999 Cal Spec Maxima SE.

Specifically, it will start reliably and idle more or less OK. It's idled better in the past but it's not about to stall or anything. If it's put into gear, it can back up, and drive forward. For about 10-20 seconds, and then power drops off and the car barely moves.

Removing the Bank 1 Sensor 1 O2 sensor(the one near the firewall) improves idle performance slightly, have not attempted to drive in this condition.

Background- I've been losing power for several months. Back in august, I replaced the fuel filter, power improved a bit but not greatly. October, new spark plugs. This was a night and day improvement... for a few days. A couple weeks ago, the car wouldn't start at all. A new fuel pump got it starting if the key was turned directly to start, but not if I paused at "on". A new fuel pressure regulator fixed that, and brought it to the performance described at the top of the post.

MAF sensor has been cleaned. In response to codes, the B1S1 O2 sensor and Camshaft Position Sensor have been replaced. Current codes, I don't recall the numbers but the CPS code is back, the B1S2 O2 sensor is throwing a code, and the knock sensor is throwing a code. I've inspected the air intake hose for leaks, as I saw that mentioned as a possible issue, it's fine.

BenL

The knock sensor is a ghost code, disregard unless it's the only code remaining in the system.

CPS would be a major concern having returned, especially if you didn't replace with an OE brand, if you haven't already you should also go ahead and clean the CKPS (POS) of metal shavings as it can mess with ignition timing and cause some odd running conditions. I clean mine at least once a year as regular maintenance, since I had experienced an odd issue where mine would buck/stumble/miss and cleaning the shavings resolved it.
Sensor 2 won't affect fuel/performance (IIRC) since it's effectively a catalyst health monitor.

Also, if you haven't recently, it might be worth a shot to clean the IAC the event that it might be sticking part-way open under throttle, causing a mild drop in vacuum pressure which would directly affect fuel pressure, MAP readings, etc. You'll likely need to perform an idle relearn afterward, however.

If you can, get all the codes that are currently present. It's hard to say for certain without all the information the car is trying to give you to work with, since some of them may seem insignificant but reveal the underlying cause.

gworroll

Found the exact codes in my Google history.

P0340 - Camshaft Position Sensor 'A' Circuit Malfunction
P0325 - Knock Sensor Circuit Malfunction
P0140 - O2 Sensor Circuit No Activity Detected Bank 1 Sensor 2


I'll try cleaning the crankshaft sensor. If it ends up that simple I'll facepalm myself(and then happily drive off somewhere).

IACV was cleaned during a failed attempt to remove the EGR tube for cleaning(the lower nuts are rusted and I can't get a grip with a wrench). 6 months to a year ago?

The main concern I've had with the O2 sensor is that it might point to a cat problem, or is that code strictly for a failed sensor rather than what it measures being out of spec?

JvG

As I recall, CS_AR had this same symptoms.

He ended up replacing a clogged cat.

Depending on emission inspection standards in yor area, you could replace the cat, gut the cat, or subsitute a test pipe.

maximaxi

That code is strictly for a failed sensor.

If the cat was no good, you'd have a code P0420

peb396

Check the muffler...have someone pressing the accelerator while holding your hand behind it...dollars to donuts, it's the muffler or cat from what you are saying

JvG

The sensor detects if the cat is functioning somewhat.

I'm sayin that the cat is physicly blocked by crud, which restricts air flow. That is what caused CS_AR s problem, and likely this one as well.

Basicly , the cat is constipated, it can't fart enough.
Too much back pressure.

Try to install a test pipe. They don't cost all that much. If performance improves, the problem is the cat.

CS_AR

Oh how I remember the winter of 2013. Looking back it is kind of funny. Except the part where I paid the dealer roughly $700 in diagnostic charges for them to tell me I had a bad engine. So I had to get the car towed home and parked in my driveway. I was ready to start parting it out and send it to the salvage yard. I decided to pull the O2 sensors to see if the problem was due to some type of exhaust restriction issue. After I pulled the O2 sensors, I was able to start and drive the car. It was loud but I could start and drive it again. Somehow I figured out that clogged/cooked cats were causing the exhaust restriction.

The underlying issue stemmed from leaking injector o-rings. It seems like I had two injectors that caused uncontrollable flooding. So I refurbished my own injectors with new o-rings, pintle caps, and screens. The fixed the flooding problem. Next I removed the cooked/clogged cats and installed a Warpspeed y-pipe. That was over three years ago. It's been running like a screaming banshee ever since.

Many of us have had to fixed the leaking injector problem. It has become such a common issue on our 4th gens, that I replaced injectors on a perfectly good running 98 model as preventative maintenance.

There are many different ways of solving the injector leak problem. You can send your injectors out for a cleaning and refurbishment by an injector service company, DIY refurbish with new o-rings, screens, and pintle caps, or purchase new injectors. Regardless of how you solve chose to refresh your injectors, the best time is to solve for it is handle it as preventative maintenance. Then you get to deal with it on YOUR terms.

Based on some failures that I've seen and private messages that I've received from other members about problems with purchasing used injectors that have been purportedly refurbished, I cannot recommend going that route. If you have healthy injectors that are working but only need new o-rings and pintle caps to solve a flooding problem, you will be better off getting your injectors refurbished.

There are many threads on how to solve the injector problem. Take a look and consider the approach that matches your skill level and pocket book.