nathaniel_h2o Posted December 19, 2011 Share Posted December 19, 2011 ok. here it goes. when my engine is cold, i can rev the engine just fine. no problems. but when the engine has warmed up and i try to rev the engine up it acts like its misfireing. it only does this between 1000-3000 rms. if i take off slow it wont do it. if i mash the gas hard, the car will stuble so hard it feels like it wants to die. so far ive changed headgaskets, valve seals, every damn oil gaskets, timing belt, belt tentioner, the timing is dead on and i have good vaccume pressure. please help if anyone has any clues what this could be. Link to comment Share on other sites More sharing options...
overspool Posted December 19, 2011 Share Posted December 19, 2011 What year is your car? Is there a check engine light? Check/clean your MAF/MAP sensor Check your spark plugs/wires as well as coil pack. Link to comment Share on other sites More sharing options...
MikeSomething Posted December 19, 2011 Share Posted December 19, 2011 I'd go for the simpler stuff man... Def change out your fuel filter if that's old... Check your air filter and throttle body also, maybe even your injectors... Link to comment Share on other sites More sharing options...
bushey45 Posted December 19, 2011 Share Posted December 19, 2011 See that box in the top right corner of your screen? That's the search box. Try using that, this issue has been covered a few times on here. Link to comment Share on other sites More sharing options...
Baddog Posted December 19, 2011 Share Posted December 19, 2011 Clogged exhaust Link to comment Share on other sites More sharing options...
overspool Posted December 19, 2011 Share Posted December 19, 2011 I'd go for the simpler stuff man... Def change out your fuel filter if that's old... Check your air filter and throttle body also, maybe even your injectors... There's no point in just throwing money at a problem and hope it's fixed (referring to fuel filter). Diagnose, then repair. It'll save you a lot of money in the long run. What could be wrong with the throttle body? Also, injectors aren't a "simple" fix, or simple diagnosis. If you've got fuel, you're good. Unless you know how to use a scan tool to it's full potential (IE fuel trims MAF etc) you won't know how to diag injectors. Link to comment Share on other sites More sharing options...
lulzcow Posted December 19, 2011 Share Posted December 19, 2011 My injectors were a simple fix. But they were easy to trace, as there was a leak because one wasn't sitting in it's place properly. If I were you, I would get some brake cleaner or "Spoof" and spray around your vacuum lines, seeing if you have a vacuum leak. If not a vacuum leak, definitely spray around various gaskets. I found a bad throttle body and intake manifold gasket in mine. Look for a fuel leak. This is how I found a seal in the fuel rail that was doubled up on O-rings, and therefore not actually sealed. And like Mike said...check the codes. Those might help you figure things out. It could even be a cheap sensor, but you won't know until you check. Throttle body could be bad many ways. The choke could be somewhat stuck and not fully rotating on throttle. The gaskets themselves could be bad. The interior of the throttle body could be dirty, restricting airflow. How clean is your air filter? Link to comment Share on other sites More sharing options...
luvmylegacy98 Posted December 19, 2011 Share Posted December 19, 2011 My car was doing the same thing. I replaced the ignition wires ($50) and fixed it right up Link to comment Share on other sites More sharing options...
nathaniel_h2o Posted December 19, 2011 Author Share Posted December 19, 2011 its a 98 with a 2.5. the intake gasket, throttle body gasket are new. new air filter. the fuel filter has less than 2000 miles on it. and i dont have any check engine lights. i do work in an auto shop and own a scan tool. when i did the head gaskets i did clean the intake manifold along with the throttle body. i have checked many times for vaccume leaks and the only leak i get out of the vaccume control solonoid (the one that sits on top of the intake) going to the EGR. but i dont think that could make a big differance. i could try new wires but i have checked those and i got plenty of spark coming from them.......oh yeah, i have tried searching this on this site and i couldnt find anything, but i am also new here so i havent figured it out all the way. Link to comment Share on other sites More sharing options...
overspool Posted December 19, 2011 Share Posted December 19, 2011 lulzcow- Ah. Leaking injectors, I was thinking clogged injectors or something lol. Watch your fuel trims and MAF reading when you go WOT. My car stumbled when I would accelerate, I ended up needing spark plug wires. I had plenty of spark, and only after driving around for 2-3 weeks with my car stumbling did it finally throw a CEL for cyl #2 misfire. Link to comment Share on other sites More sharing options...
lulzcow Posted December 19, 2011 Share Posted December 19, 2011 And maybe if it isn't the wires, it is the plugs themselves. You could see if they are Bosch or whatever. If they are, it'd be a good idea to go ahead and replace them with NGKs. My Bosch plugs would make it feel like a backfire almost at WOT or high RPM, and were inconsistent in doing so. Also, they'd let them engine stumble returning to idle after low throttle input. Not the case with NGKs in. I think many others have had inconsistencies with the Bosch plugs in our cars also Link to comment Share on other sites More sharing options...
nathaniel_h2o Posted December 20, 2011 Author Share Posted December 20, 2011 yeah, i do have bosh plugs in. good call. and i am not throwing any codes. i am starting to think its the lifters. cause i got them mixed up when i was putting them back into the heads. it could be an exhaust valve not opening all the way to let all the pressure out, or an intaking not letting enough air in. and it deosnt do it when its cold. Link to comment Share on other sites More sharing options...
lulzcow Posted December 20, 2011 Share Posted December 20, 2011 That sounds like a hassle of a fix! Link to comment Share on other sites More sharing options...
nathaniel_h2o Posted December 21, 2011 Author Share Posted December 21, 2011 it is, but im going to see if its the coolant temp sensor first. that could do it too...i think Link to comment Share on other sites More sharing options...
overspool Posted December 21, 2011 Share Posted December 21, 2011 You would normally have a CEL for a failed temperature sensor if it is bad enough to cause the car to run weird. Link to comment Share on other sites More sharing options...
kt240240 Posted December 21, 2011 Share Posted December 21, 2011 if you have access to a fuel pressure gauge i would say plug that in, after the fuel filter, and that will diagnose and problem with fuel right up to the injectors, i think the specs for pressure on a 2.5 is 35psi at idle. when my car's fuel pump was going i had almost no power, its an easy test and just another thing you can check off the list, fuel pressure gauge kits you can rent from auto zone or whatever for free Link to comment Share on other sites More sharing options...
overspool Posted December 21, 2011 Share Posted December 21, 2011 whoops wrong thread. Link to comment Share on other sites More sharing options...
nathaniel_h2o Posted December 21, 2011 Author Share Posted December 21, 2011 hmmm... check this out. i ran another smoke test on it and was leaking out the valve covers pretty bad. so i took them off, cleaned both surfaces and put some rtv around the camshaft retainers edges and put it all back togther and now no leak. and i also replaced the thermostat cause it was starting to stick. and now it runs good now. so i guess it was the valve cover leaks causing a big vaccume leak. hmmm Link to comment Share on other sites More sharing options...
overspool Posted December 21, 2011 Share Posted December 21, 2011 Woah. Very interesting... normally vacuum leaks would be apparent on idle but not under acceleration, because at idle your in vacuum, and when accelerating you should be at atmospheric pressure. Link to comment Share on other sites More sharing options...
nathaniel_h2o Posted December 23, 2011 Author Share Posted December 23, 2011 i know. its sounds weird. thats all i did too and it worked. i did unplug and replug the two coolant temp sensors. maybe they were not hooked up completley Link to comment Share on other sites More sharing options...
overspool Posted December 24, 2011 Share Posted December 24, 2011 we have 2 coolant temp sensors? holy crapp! lol. Your coolant temp sensors could of had just enough dirt/crud on them that they weren't reading correctly. Link to comment Share on other sites More sharing options...
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