Recently bought a 1996 F150 w/ 345k on the clock. Got it for next to nothing, so I expected to have a few problems to work out. The truck has a little trouble starting, but so far has eventually gotten going every time after a few seconds. I do notice a rough idle at times, but it hasn't stalled on me -- yet. When I took it in for an emissions inspection, it failed due to two separate codes:

• P0141
• P0147

My mechanic said he found a vacuum leak and repaired it. He retested the truck and it passed, but about halfway home, the CEL came on again. When I scanned the OBD, I got the same two codes as before, plus one that didn't show up on my original emissions test: P0420, which has something to do with a catalytic converter I think.

Anyone have a suggestion as to where I should look next? I'm not interested in spending a lot of money on repairs due to the high mileage and low cost of the truck (paid $700), so I'm hoping to be able to work on it myself instead of paying $65 an hour. I only use it on weekends, and even then it's only a few miles at a time for local errands that I can't do in my everyday driver.

Any and all help would be appreciated!

 

Spring for a repair manual, a can of Seafoam & a can of electronic contact cleaner. slowly pour 2/3 can (seafoam)in the end of the power brake boster vac hose after disconnect at booster.allow idle to stumble as low as possible w/o stalling then shut off for 10-15 minutes. pour the remainder into tank restart & rev til smoke clears. remove, deuch w/ contact cleamer spray, the MAF sensor EGR valve,IAC valve, also O2 sensors and reinstall. before anything disconnect battery and don't reconnect for at least 20 minutes. service all items listed all same time .20 min battery discon. covers all repairs . if serviced seporatly 20 min discon. each time. This clears the Kam and rebuilds learn strategy info tables. The O2 sensors switch rate will usualy improve immeadiatly , but should replace soon. and "STiCK TO 87 OCTANE" unless you want to supersize your existing can of worms.

 

WOW. Thank you for all that info. Interesting that you mentioned 87 octane in big, bold letters. When I test drove the truck, it seemed to be a lot smoother than it is now. It was almost out of gas when I picked it up, so I filled it -- with 89 octane. Do you think it could just be an issue with the fuel? The front tank is almost completely empty, so I'll fill it with 87 and run off that to see if it improves. I've only put about 70 miles on the truck using the 89 octane, so hopefully I didn't do too much damage.

What's the reason for avoiding the 89 octane? I've always assumed that the "better" gas would improve any vehicle's performance, but apparently I was totally wrong.