Hey all,

Well I fixed up that truck for my friend and wouldn't you know two weeks after I give it to him it gives up outside chicago and he's stuck. Sucks. He's got a multiple cylinder misfire, several codes in the p0300 series and it won't shift out of second or go over 40 mph. Any ideas? I think I'm hoping for a clogged cat? Weld in a universal and on with life?

99 4x4 5.9 by the way.

 

Could all well be. Pull the front O2 sensor out of the exhaust, see if it runs any better.

 

Clogged cat would not be my first guess. Normally that doesn't cause misfires, the other way around extensive misfiring could cause cat damage. 99 is obdII so you can check 02 sensors. Fuel pressure or major intake leak, maybe crank or cam position sensor could be culprits.

 

Well here's the update. Got the thing towed, some shop thought it was the fuel pump (sounded off to me). DIdn't fix it. Didn't charge for the tow or the repair which I thought was good of them.

Towed it to an exhaust shop, confirmed the cat had melted down. Put a new cat and a downstream O2 sensor in it. Now its running more normal. He can do highway speeds with the thing.

New problems are these: as soon as he pulled away from the shop he had p0711 and p1763. Not sure what they must have done to this thing to mess up the trans temp sensor, but I figured in 20 degree Chicago after the truck has been sitting all day, its not a heat issue its a sensor issue. So now it's down on power with no 4th gear, but since he had no choice he drove it. To Utah. Slowly. And it seems like its actually running fine in what must be limp mode. Go figure. He's actually on the west tip of Wyoming as I write.

Apparently there was snow/blowing winds/no visibility in Wyoming and he stuck it in 4x4 to stay on the road. The brake and ABS light came on when the 4x4 engaged. Any ideas on that one?! He has a good pedal. Cruise control is not working since those lights came on.

Thanks all-

 

The code setting criteria for both codes includes faulty wiring (open or shorted) and as the shop worked down in that vicinity I'd venture that's related (but I've been wrong before, see above... ). The connectors on the transmission are on the opposite side of the cat and O2 sensors but come out the same wiring loom.

Cruise control doesn't work when the ABS and brake warning comes on, faulty readings from the speed sensor(s) could throw off the CC. The ABS module does have a 4WD input that gets a signal when the 4WD light comes on in the dash (they are both connected to the switch at the axle). Don't have a really good idea why that input would trigger an error in the ABS module. I'd try a few things: Put it in 2WD, turn the truck off and on in both 4WD and 2WD to see if clears.

 

Thanks for the follow up. Looks like the brake abs lights cleared next time the truck was shut off (in 2wd).

 

The transmission codes are the temperature and governor pressure sensors. Looking at the wiring diagram they share the sensor ground at the ECM with the O2 sensors. If the shop messed up the wiring at the sensor or used a random generic one that might cause the issues.