98 blazer, 195K. After navigating Houston flood waters for 25 miles I hit really high water (1-2" up door) less than a block from my driveway..arggg. after pushing home, had a no crank start. removed plugs, purged water, replaced plugs and wires. Dried out air intake (took in water), replaced air filter. cranked and Engine was not seized YAY!!, but had white smoke and choc milk oil. Dreading blown head gasket repair, I changed oil/filter, ran for a few min.. smoke disappeared! Ran Compression leak test, had blue liquid! so far so good. Now I am left with 1500rpm idle in park, a normal 1000rpm in drive, and low sluggish 600rpm when braking. Plan to check error code to asses a possible bad MAF, TPS, IAC, ERG or MAP or maybe vac leak. Noticed vacuum line on air intake is very loose at valve cover. also since buying truck have never replaced MAF, PCV, TPS or IAC. Throttle cable is loose (not binding) and cruise control cable is detached due to broken clip.

Hoping for some advice for this specific high idle in park, normal in drive situation. Thanks in advance for any tips, clues or reply's.

 

Checked error codes, had the MAF code. already in process replacing the PCV, IAC and TPS, also thermostat while i'm there. Assuming due to amount of water takin in through air intake the MAF is toast, so planning on replacement not cleaning current one.

 

Fixed! cleaned MAF with correct cleaner, put in new PCV, IAC and TPS and thermostat while I had the upper RAD house off. Operating temp at perfect 185, idle at 600rpm. Looks like the post flood idle was the TPS. even got a 30% discount at PB's, so all in all I spent under 300 and it runs perfect now.