# Engine starts rough when warmed up & left to sit for 5-15 minutes **URL:** \ **Category:** Stock Engine-Bay Components\ **Created:** [July 9, 2012, 6:52pm UTC](https://forum.g2ic.com/t/engine-starts-rough-when-warmed-up-left-to-sit-for-5-15-minutes/96499 "2012-07-09T18:52:23Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![djzachtyler](https://forum.g2ic.com/letter_avatar_proxy/v4/letter/d/a183cd/32.png) [@djzachtyler](https://forum.g2ic.com/u/djzachtyler)\ **Post date:** [July 9, 2012, 6:52pm UTC](https://forum.g2ic.com/t/engine-starts-rough-when-warmed-up-left-to-sit-for-5-15-minutes/96499/1 "2012-07-09T18:52:23Z")
Hey folks… I already have a few ideas what this issue could be related to based on past car experience, but after completely changing out my cooling system (New radiator, hoses, T-Stat, cooling fans) , and ignition system (New cap, rotor, plugs, & wires) I am having an issue where after my car reaches operational temp, if I park it and go in the store for 5-20 minutes and come back out it will start rweally rough and misfire like crazy… The issue has been getting progressively worse, & today when leaving Acura service center after getting a seatbelt issue fixed, the car wouldn’t start. took several attempts before the engine finally caught and stayed running. the misfire issue will stop shortly after the engine starts, and once on the road goes away completely. I pulled the plugs not long ago to check for any funky deposits, and they looked fine (no white residue or completely blackend coloring) This issue is not present during cold starts or if the car sits an hour or more. I’m stumpeed though and am hoping ther emight be something else I can try to do before I just give in and turn the car over to my mechanic… ---
**Author:** ![integrajdmjada](https://forum.g2ic.com/letter_avatar_proxy/v4/letter/i/4491bb/32.png) [@integrajdmjada](https://forum.g2ic.com/u/integrajdmjada)\ **Post date:** [July 10, 2012, 4:04pm UTC](https://forum.g2ic.com/t/engine-starts-rough-when-warmed-up-left-to-sit-for-5-15-minutes/96499/2 "2012-07-10T16:04:15Z")
might be a bad oil pump sir, it may not be pumping enough oil into the motor right away. Or dirty injectors ---
**Author:** ![djzachtyler](https://forum.g2ic.com/letter_avatar_proxy/v4/letter/d/a183cd/32.png) [@djzachtyler](https://forum.g2ic.com/u/djzachtyler)\ **Post date:** [July 10, 2012, 4:16pm UTC](https://forum.g2ic.com/t/engine-starts-rough-when-warmed-up-left-to-sit-for-5-15-minutes/96499/3 "2012-07-10T16:16:33Z")
I’m leaning toward dirty injectors… cheap gas and vapor lock. Oil pump is a maybe, but I got flow to the top of the engine and good pressure. ---
**Author:** ![92lsDa9](https://forum.g2ic.com/letter_avatar_proxy/v4/letter/9/ea5d25/32.png) [@92lsDa9](https://forum.g2ic.com/u/92lsDa9)\ **Post date:** [July 12, 2012, 1:42pm UTC](https://forum.g2ic.com/t/engine-starts-rough-when-warmed-up-left-to-sit-for-5-15-minutes/96499/4 "2012-07-12T13:42:18Z")
you said you’ve got new cap rotor wires and plugs… but your coil or ignitor is probably going out…I would change that next. ---
**Author:** ![djzachtyler](https://forum.g2ic.com/letter_avatar_proxy/v4/letter/d/a183cd/32.png) [@djzachtyler](https://forum.g2ic.com/u/djzachtyler)\ **Post date:** [July 12, 2012, 6:52pm UTC](https://forum.g2ic.com/t/engine-starts-rough-when-warmed-up-left-to-sit-for-5-15-minutes/96499/5 "2012-07-12T18:52:17Z")
will do… I just happen to have a spare ditributor in the garage I can swap parts out of for testing purposes. My biggest fear is that I have some catastrophic engine crap going on… that would put me over the top on maintaining this car, but at this point I’m not gonna trash it either. ---
**Author:** ![djzachtyler](https://forum.g2ic.com/letter_avatar_proxy/v4/letter/d/a183cd/32.png) [@djzachtyler](https://forum.g2ic.com/u/djzachtyler)\ **Post date:** [July 15, 2012, 1:34am UTC](https://forum.g2ic.com/t/engine-starts-rough-when-warmed-up-left-to-sit-for-5-15-minutes/96499/6 "2012-07-15T01:34:54Z")
Ok… So my issue has gotten worse today and is drivin me nuts… I pulled all my plugs and i am gettingspark across all 4 just fine. Found all sorts of whit crap crusted around the #4 plug below the ceramic where the plug sits in the valve cover. I d ecided to check compression and have 175, 175,170,175 across the board. Only change was i removed the resonator from under the filter box as i was going to install my cai. Unfortunately i was missing a part and ended up leaving the stock intake and filter box minus the resonator deal… Engine justdoesn’t Want to start for shit. Once it is running all is fine… This has me going crazy. Cant get in to see my mechanic for almost a week and 5 dayz… Checked my relays they all look good from what i can tell… No smoke from exhaust also… So do not think i have a head gasket issue. Im baffled. May try swapping ou gt my distributor next but i got good spark. So not sure that is gonna make a difference. ---
**Author:** ![unified112](https://forum.g2ic.com/letter_avatar_proxy/v4/letter/u/41988e/32.png) [@unified112](https://forum.g2ic.com/u/unified112)\ **Post date:** [July 15, 2012, 1:42am UTC](https://forum.g2ic.com/t/engine-starts-rough-when-warmed-up-left-to-sit-for-5-15-minutes/96499/7 "2012-07-15T01:42:47Z")
> [@92lsDa9;2265630](#): > > you said you’ve got new cap rotor wires and plugs… but your coil or ignitor is probably going out…I would change that next. This. A bad coil can cause problems like this ---
**Author:** ![djzachtyler](https://forum.g2ic.com/letter_avatar_proxy/v4/letter/d/a183cd/32.png) [@djzachtyler](https://forum.g2ic.com/u/djzachtyler)\ **Post date:** [July 15, 2012, 5:31am UTC](https://forum.g2ic.com/t/engine-starts-rough-when-warmed-up-left-to-sit-for-5-15-minutes/96499/8 "2012-07-15T05:31:09Z")
so I did a coil test and believe you guys are spot on… only getting .23 ohms resistance betweeen the +/- terminals… Secondary test was ok @14.57… the real kicker is that my other coild has .71 ohms between +/- terminals, but fails secondary test with only 12.38 ohms resistance… looks like I am going shopping locally for a new coil tomorrow, which sucks balls cause they are like 60 bucks at o’reillys… 56 bucks for a crap one at Auto ZOne, and at JC whitney on line they are a whopping $15.97 ---
**Author:** ![unified112](https://forum.g2ic.com/letter_avatar_proxy/v4/letter/u/41988e/32.png) [@unified112](https://forum.g2ic.com/u/unified112)\ **Post date:** [July 15, 2012, 5:35am UTC](https://forum.g2ic.com/t/engine-starts-rough-when-warmed-up-left-to-sit-for-5-15-minutes/96499/9 "2012-07-15T05:35:14Z")
Honestly, I’ve had two AutoZone coils fail the ohm test right out of the box… Take your multimeter with you when you buy one. ---
**Author:** ![djzachtyler](https://forum.g2ic.com/letter_avatar_proxy/v4/letter/d/a183cd/32.png) [@djzachtyler](https://forum.g2ic.com/u/djzachtyler)\ **Post date:** [July 15, 2012, 6:13am UTC](https://forum.g2ic.com/t/engine-starts-rough-when-warmed-up-left-to-sit-for-5-15-minutes/96499/10 "2012-07-15T06:13:54Z")
thanks… was planning on it. ight be able to get away with using that spare for now… the secondary test is barely below standard ---
**Author:** ![unified112](https://forum.g2ic.com/letter_avatar_proxy/v4/letter/u/41988e/32.png) [@unified112](https://forum.g2ic.com/u/unified112)\ **Post date:** [July 15, 2012, 6:21am UTC](https://forum.g2ic.com/t/engine-starts-rough-when-warmed-up-left-to-sit-for-5-15-minutes/96499/11 "2012-07-15T06:21:04Z")
I suppose it’s worth a shot. See if it hurts it helps in any way. ---
**Author:** ![djzachtyler](https://forum.g2ic.com/letter_avatar_proxy/v4/letter/d/a183cd/32.png) [@djzachtyler](https://forum.g2ic.com/u/djzachtyler)\ **Post date:** [July 16, 2012, 12:05am UTC](https://forum.g2ic.com/t/engine-starts-rough-when-warmed-up-left-to-sit-for-5-15-minutes/96499/12 "2012-07-16T00:05:32Z")
put a new coil in… decided not to hassle with the used one… First start was still getting a little bit of a misfire. will let it sit fr a few and see what happens in 10-15 minutes. the way this keeps going ima be a acura pro haha ---
**Author:** ![djzachtyler](https://forum.g2ic.com/letter_avatar_proxy/v4/letter/d/a183cd/32.png) [@djzachtyler](https://forum.g2ic.com/u/djzachtyler)\ **Post date:** [July 16, 2012, 10:56pm UTC](https://forum.g2ic.com/t/engine-starts-rough-when-warmed-up-left-to-sit-for-5-15-minutes/96499/13 "2012-07-16T22:56:30Z")
so all was well for about a day and now the issue is back… plus when I start the car it is blowing smoke… gonna pull that new coil and see what is… be hard to believe a new one is bad already… this is getting aggrivating. ---
**Author:** ![djzachtyler](https://forum.g2ic.com/letter_avatar_proxy/v4/letter/d/a183cd/32.png) [@djzachtyler](https://forum.g2ic.com/u/djzachtyler)\ **Post date:** [July 17, 2012, 2:14am UTC](https://forum.g2ic.com/t/engine-starts-rough-when-warmed-up-left-to-sit-for-5-15-minutes/96499/14 "2012-07-17T02:14:04Z")
SPoke with a mechanic and he is sayin to just replace the entire distributor. something about a cam position sensor. Guess I can return that coil and get my $$ back ( I hope) flip side I found a new distributor for 85 bucks on fleabay that is ODB0 but uses the coil, cap & rotor like on the 92-93 tegs… Looks like I’ll be able to make use of my Accel cap n rotor set after all lol. Also think I have ruled out the main relay which can also cause this issue. I definitely hear a click when it CEL turns off after 2 seconds with the keyin the on position (car not fully started) All the damn smoke it was blowing yesterday was completely gone again this morning when I went out for the first start of the day… wonder what it is going to be like when I leave the office lol. ---
**Author:** ![djzachtyler](https://forum.g2ic.com/letter_avatar_proxy/v4/letter/d/a183cd/32.png) [@djzachtyler](https://forum.g2ic.com/u/djzachtyler)\ **Post date:** [July 18, 2012, 3:44pm UTC](https://forum.g2ic.com/t/engine-starts-rough-when-warmed-up-left-to-sit-for-5-15-minutes/96499/15 "2012-07-18T15:44:03Z")
ok so I am going overboard on parts, but just ordered a new distributor, and a buncha spare parts for the ignition. found a MAP sensor for a decent price, TPS sensor o2 sensor… new vacuum hose. on the flip side when I went to oreilly’s the Asst. manager there was a teg owner, and when I popped the hood for him to have a gander his immediate response was “Oh Damn that is nice!” I thanked him lol. Will try to get some pics posted on my thread soon the engine has come a long way since my first set of pics. ---
**Author:** ![welfare](https://forum.g2ic.com/letter_avatar_proxy/v4/letter/w/85f322/32.png) [@welfare](https://forum.g2ic.com/u/welfare)\ **Post date:** [July 20, 2012, 2:54am UTC](https://forum.g2ic.com/t/engine-starts-rough-when-warmed-up-left-to-sit-for-5-15-minutes/96499/16 "2012-07-20T02:54:29Z")
i’m thinking iacv issue. sticking. the iac should open when the vehicle is shut off. it could be sticking open causing a lean misfire. your mech may be on a goose chase. the cam position code gets thrown out sometimes with misfires. try cleaning the iacv. hmmm but that should cause a high idle. i’d clean it anyways. it’s free and worth a shot. might even be sticking shut. not 100% sure on its position at rest ---
**Author:** ![djzachtyler](https://forum.g2ic.com/letter_avatar_proxy/v4/letter/d/a183cd/32.png) [@djzachtyler](https://forum.g2ic.com/u/djzachtyler)\ **Post date:** [July 21, 2012, 2:30am UTC](https://forum.g2ic.com/t/engine-starts-rough-when-warmed-up-left-to-sit-for-5-15-minutes/96499/17 "2012-07-21T02:30:32Z")
More like I am the one on the goose chase lol. I got all new stuff to install over the weekend, so if this doesn’t resolve it I’ll just make sure that I plan on stayin where I am for at least an hour haha. By the time all is said and done I may not need the mechanic… ---
**Author:** ![welfare](https://forum.g2ic.com/letter_avatar_proxy/v4/letter/w/85f322/32.png) [@welfare](https://forum.g2ic.com/u/welfare)\ **Post date:** [July 21, 2012, 3:41am UTC](https://forum.g2ic.com/t/engine-starts-rough-when-warmed-up-left-to-sit-for-5-15-minutes/96499/18 "2012-07-21T03:41:44Z")
did you actually test any of the parts you’re planning on changing? all those components are easy to qualify have you checked for codes yourself yet? ---
**Author:** ![djzachtyler](https://forum.g2ic.com/letter_avatar_proxy/v4/letter/d/a183cd/32.png) [@djzachtyler](https://forum.g2ic.com/u/djzachtyler)\ **Post date:** [July 21, 2012, 2:05pm UTC](https://forum.g2ic.com/t/engine-starts-rough-when-warmed-up-left-to-sit-for-5-15-minutes/96499/19 "2012-07-21T14:05:28Z")
that is the bitch about it… no codes. not even during the rough start. My multimeter has gotten more use in the last week than it has in years. but yeah most stuff checks out. well except that Crank or cam sensor deal in the distributor… haven’t tested that as I do not know what part it is. ---
**Author:** ![welfare](https://forum.g2ic.com/letter_avatar_proxy/v4/letter/w/85f322/32.png) [@welfare](https://forum.g2ic.com/u/welfare)\ **Post date:** [July 21, 2012, 4:55pm UTC](https://forum.g2ic.com/t/engine-starts-rough-when-warmed-up-left-to-sit-for-5-15-minutes/96499/20 "2012-07-21T16:55:07Z")
the cam and crank sensors are magnetic pulse generators located in the distributor. i doubt they are the problem since the issue only occurs on start up. also, a bad crank sensor would keep the car from running at all. ideally, for PM generators, you’d want to use an oscilloscope to view the AC sine wave and look for irregularities. but as mentioned, the problem only occurs on start up, so it’s not likely. what year is the car? and you’re actually checking for codes, yes? not just the MIL? because codes will be set before they illuminate the MIL [Next page](https://forum.g2ic.com/t/engine-starts-rough-when-warmed-up-left-to-sit-for-5-15-minutes/96499.md?page=2)