bronco ii intermittant rough run > warm up

[djbusch]

I have an 88 bronco II, 2.9 v6. About two weeks after replacing the gas tank, it started running rough (black exhaust) intermittantly only after warm up. The rough running is for about ten seconds then runs good for about a minute before starting the cycle over again. The fuel filter, dist. cap and rotor, and ECT switch have been replaced. Plugs, coil and wire resistance are ok with no trouble codes other than the ever present 67 (NDS, CS etc.). Any suggestions would be welcome.

[djbusch]

Found it - it was the map sensor which didn't
show on the diagnostics

[djbusch]

Ran good for one week, back to original problem

[sheets]

I have the same problem with our Bronco 2. It also has the 2.9 v6. The engine codes I get are 18 and 42 for service codes. The temprorary code is 41. I've replaced the coolant sensor , TFI module, Dist. cap, and plugs. The problem goes away for a day or two and comes back. The engine on this seems to loose almost all power for 5-10 seconds then comes right back. Maybe it's the O2 sensor? Any ideas

[djbusch]

Took the first MAP sensor back to Advance Auto and they gave me a replacement. Before installing it I erased all trouble codes then installed the sensor and it has been running fine since!

[kingmt]

Originally Posted by sheets

I have the same problem with our Bronco 2. It also has the 2.9 v6. The engine codes I get are 18 and 42 for service codes. The temprorary code is 41. I've replaced the coolant sensor , TFI module, Dist. cap, and plugs. The problem goes away for a day or two and comes back. The engine on this seems to loose almost all power for 5-10 seconds then comes right back. Maybe it's the O2 sensor? Any ideas

I'm a littel rusty on obd I code but I think that is a EGR, EPV, & O2 code. If you take the EPV off & put an empty .22cal shell caseing on it's plonger it will make up for the ware. This happens to the EPV's about every 80,000 miles. I laft the caseing on mine & have never had the problem again but I not tell you to use it as a purmitt fix just to test it for two weeks.