Working on a 1998 EX Civic with a hesitation problem. I have seen tons of posts about this issue but none of them have the "official" problem listed. I have scanned and have no codes also checked all sensors as far as tps has no dead spots and has correct voltage throughout entire range of throttle. MAP sensor is reading correctly even under loads while misfire is happening. Again no codes being set by bad misfires. changed the primary O2 sensor it has a new cat on it as of only 2 weeks ago... it is aftermarket junk but that was customer request and its the second one we have done on this car in a year... so anyways fuel pressure is good and all seems well. It doesn't start having problems until ECT reaches at least 220 and then it can almost do it on command just hold down bakes and put in drive and you can duplicate problem sitting still.

so if anyone has had this issue i would love some good insight ive checked everything else im wondering next if i should check the crank sensor but there is no inspection point inside of my snap-on solus for it.. thanks for whatever help i do get.

-Autossey tech

 

If the coolant temp reaches 220F, then the engine is overheating.

Last full ignition system tune up?

Has the ignition timing been set to spec?

 

220 may be an exaggeration more around just op temp at 200 ish... ignition system is good plugs are correct gap and ngk its only under load... no issues as far as rotor or cap goes all fairly new

 

timing is set to specs no issues there.

 

Does unplugging the primary O2 sensor prevent the problem?

How old are the plug wires?

Is the FPR working properly?

 

Fuel pressure is within specs.

plug wires are between 4-6 months old OEM replacement.

and no unplugging primary O2 doesn't change anything.

still scrambling my mind on this been trying a bunch of different things trying to test out all the options and cant find anything that makes it stop happening.