car isnt running well....help me fix it tomorrow

[HazMat404]

alright...havin troubles with my car again. my exhaust leak came back so im gonna try and fix that up. but my problem seems to lie within the engine now. up to about 2500rpms it seems to be pretty decent, just a lil slower than normal i guess. well after that 2500 to about 3500-4000rpms it chugs...and by chugging i mean it chugs pretty good. after about 3500-4000 rpms it pretty much falls on its face.

fuel pressure is at 35 w/ vac on and 42ish w/out, car ran fine for awhile after i fixed my exhaust leak about a week or so ago, the leak i have no is about 1/4 as bad as it was before so its not that but im scared that something happened to one of the valves. i think having the exhaust leak that long then having it fixed for a week then having it leak again might have caused some damage.

aside from a compression test, what else can i do to check anything that it can be?? tomorrow is one of my only days off and im probably going to be getting a new job with my uncle that is a good hour drive away so ill need my car fixed very soon if something is wrong with it. any help is appreciated a ton

 

[RIO5.0]

Plugs, cap, rotor look decent???? MAFs clean, plugwires decent, the basic stuff ??

Is it running smooth up to the rpm range and then falling on its face???

does it reek of fuel, woofing gas bigtime, puffing black smoke when you hit the throttle??

Exh leak to me wouldn't really cause damage, not like your gonna wreck your valves or something from a leak...

 

[HazMat404]

well at the time it was a good exhaust leak. ive heard of bad stories of messin up valves bad but im prayin its not that. maf is clean with the air filter (about 1k mile ago and cleaned maf again after about 200 mile of driving due to oil run off of k&n), changing fuel filter, pcv filter and anything else i can think of cause its been near 8k miles since ive done that.

it pretty much runs "semi" normal til about 3000rpms then it just chugs then later falls on its face. i really cant think of what it is and i dont want to pull the heads again because i reworked the engine about 1200 miles ago and my pops would be mad id have to do that again (and of course id have to buy 1.7rr ) but still......


im just tryin to think of what it can be. everything ran fine for awhile after i fixed my leak but then it kinda sorta came back super slowly and my car falls on its face. im prayin its not a valve. im hoping the "ticking" sound goes away with the exhaust cause it really sounds like an exhaust leak but im only 95% sure of that. also....the car doesnt buck when i hold down the clutch no matter what speed im at (100mph, 50mph or 10mph)


oh yeah, reread the reply. f/p is good....ive tinkered with it a ton and it hasnt doen anything so its back to 41 w/out vac. i doubt anyting really went bad outta the blue but im hoping it is something simple that im not htinkgin about. cap, rotor were replaced about 2k miles ago along with the refreshened motor. it ran strong about 2 weeks ago when i fixed my month long exhaust leak and then the leak came back after about a week so thats why im afraid of a floating valve or something.....compression tests tomorrow...

 

[1fstgt]

sounds like a clogged fuel filter to me. but without actually seeing what it's doing it's hard to tell.

 

[mo_dingo]

Here is your order of operation tomorrow.

1) Run codes. Can't hurt. Might lead you somewhere.

1a) Remove MAF/IAT sensors and re-clean them. The filter might have clogged them back up. Check all vacuum/fuel lines. Spray 1/2 can of carb cleaner into TB while engine is running at fast idle. Test drive car.

2) Remove, note cylinder#, inspect and (replace if necessary) all spark plugs. Note if you are running rich/lean and in which cylinder this is occuring. Check gap also. File down any corrosion built up on the cap/rotor metal contacts. If corrosion is too bad, replace as necessary.

3) If ALL plugs are lean/rich, (replace all plugs or file down marks if plugs are still good), bump FP up slightly. Test drive. If running bad still, yank plugs, and check for lean/rich. Repeat process until plugs remain clean (dirt brown = ok).

4) If only 1 cylinder is running lean/rich, replace spark plug wire and spark plug. Test drive, then yank the plug again to check for running lean/rich. If condition persists, perform compression test.

NOTE: You should run a compression test while you have each spark plug removed. I think numbers should be above 100 PSI, and all within 10% of each other. It sucks to think that this could be your problem, but then again it sucks even worse chasing down a dead horse. I think you can rent the compression tester @ autozone, but call first. I remember trying to get one, and having problems finding one.

Good luck. I am battling an idle problem when I get back from my ski trip on tuesday, so I feel your pain.
Scott

 

[HazMat404]

cool...im gonna start cleaning and checkin everything now. i forgot to say that i rebuilt my engine about 2k miles ago because of a cracked valve. ive got a compression tester so that is definately something i will do but i doubt it will show anything. im hopin it is as simple as a spark plug but we will find out.

thanx for the ideas. im gonna start my search now and hopefully later ill tell ya guy what i have found