Lean exhaust and other codes

[ouray19]

Thanks Dustin for the suggestion but I don't believe I have this sensor on my truck. I have a MAP sensor next to the TBI.

 

[ouray19]

Just replaced the O2 sensor and that took care of the stalling. No more error codes. Still runs a little sluggish but will complete the whole tune-up.
I want to service the transmission hoping that will help. According to service records, tranny was serviced about 60K miles ago but not sure what is meant by servicing. I have heard that flushing will replace the fluid but does not replace the filter. The fluid is a little dirty and smells used but not burnt. I want to keep this truck for a long time and just wondering what is the best maintenance to prevent problems down the road.

 

[ouray19]

So, the issues returned a few days after replacing the O2 sensor. Hard starting, stalling and missing out. Put it up on a lift and found the cat was plugged and the exhaust system was full of leaks. Replaced the cat and a new cat-back exhaust system and again, made the truck run good again. A few days later, started missing a little bit, but not near as bad as before. SES light comes on intermittent and again shows code 44, lean exhaust. Seems to run great at 1800 RPM's and above, but when it sits at idle in gear, there is a constant miss and sometimes stalls. Also noticed that at idle, the oil pressure gauge bounces but seems to level out at higher rpm's. Not losing any oil. Think there might be any correlation between the oil gauge bouncing and missing out at lower rpm's?

 

[ouray19]

Wanted to give an update on the issues I have been having. For the last couple months, I have still been having a rough idle, stutter when taking away from a stop and still getting an occasional code 44 lean exhaust. I have been lucky enough to have another 95 350 tbi to steal parts from (this truck ran great until it got rear ended and totaled it).
So today, I thought I might try a relearn for the AIC and when I disconnected the negative to clear codes, I notice my positive cable had a little bulge at the connection, probably from corrosion build up. So tonight, I pulled the positive cables that go to both the starter/alternator and to the relay center and put the cables from my parts truck on. WOW! what a difference. No more stutter, stalling and poor acceleration and no more SES light. My guess is that I was not getting enough voltage to the relay center or the rest of the other components in the system and with the new cable, now plenty of voltage and a great running truck again.
This may not resolve issues other people are having but just thought I would throw it out to everyone in case it may help somebody else.

 

[chipskittles]

Thanks for the update i'm glad you got it figured out. Bad power and/or grounds will cause this kind of stuff because the sensors don't have a good reference.

 

[ouray19]

Well, the truck had been running very well for a couple months but recently, it started doing it's old habits. The problems started again having a rough idle, stutter when taking away from a stop and still getting an occasional code 44 lean exhaust. Runs rough until it gets to about 2500 RPM's then kicks in and runs strong. Anything below 2500 RPM's and it runs rough and lacks power. Any thoughts????

 

[ouray19]

Truck seems to run good when you first start in the morning. After it runs for about 15 minutes, the rough idle and stutter start. Then again, each time you start it for the rest of the day, it runs rough. Would a bad catalytic converter cause this type of problem? How does one know if the cat is going bad? Any way to test them?

 

[smdk2500]

one way to tell is by temp difference between the inlet and outlets. the outlet should be hotter then the inlet. easiest way is with a thermal camera ive found a few for guys at work that where bad. But not every one has one of those or are cheaply bought. you could probably use a temp gun and check it that way. Ive also heard of with the engine running put you hand on the tail pipe and covering it your hand should be pushed off forcibly if not i could be plugged. But that only would work on single cat systems or if you have dual cats and dual exhaust.

 

[Schurkey]

Truck seems to run good when you first start in the morning. After it runs for about 15 minutes, the rough idle and stutter start. Then again, each time you start it for the rest of the day, it runs rough. Would a bad catalytic converter cause this type of problem? How does one know if the cat is going bad? Any way to test them?

There's nothing in the catalytic converter that "changes" after running for 15 minutes to cause a rough idle.

Get a scan tool, check the data stream.

 

[ouray19]

Thanks for your input. Any suggestions on a good scan tool for the OBD1?