QuestionQUESTION: hi todd
u help me back in 08 with a ignition problem. module was bad.
need your help again. car gets flopy and jerky after warm up going done the road.jest replace timing belt and coolant temp sensor yesterday. oxygen sensor a month ago. air filter distributor and cap and rotor also . timing belt was strectch ,new is set dead on center ,check three times. i set
timing at 8 degrees . at idle it runs smooth and with no motor movemet . sounds great. but after its at operating temp running down the the road it that when the problem start. pull back in drive and while in park and running. reving motor up it just pop and sputters. higher the the rpm the more it does it. 115,000 miles on car. going back a few years. cam and lifters replaces. use to bump timing up a couple dergres to make it run smoother with great results. every couple years check timing and fell back to 8 degress . bump and again and fall back 8 or so after a couple years. probably strecth timing belt because of doing that so now its all replaced. problem started a month after warm . it would buck and jerk, not enough to stall but enough to not drive and more till cool down . usally drive is 3 to 10 miles. move timing to 6 degrees ran o,k for a couple of weeks. just a little pop out the exhaust reving in park then it ran great after replacng parts metion above. till warm and starts it again. plugs are good cat convter new 20,000 miles a go. it acts like after warm and driving timing not advancing and running lean. could it the the map sensor or some thing check all vaccum line for links all ok. plus i replaced them 6 years ago. no moisture in tank and always ran good fuel injector cleaner about 3 months. and only run shell gasoline. any suggestion would be great to check out next. it only does after operating tempture . your awsome todd .need your help again
use to bump timing up a couple dergres to make it run smoother with great results. every couple years check timing and fell back to 8 degress . bump and again and fall back 8 or so after a couple years. probably strecth timing belt because of doing that so now its all replaced. problem started a month after warm . it would buck and jerk, not enough to stall but enough to not drive and more till cool down . usally drive is 3 to 10 miles. move timing to 6 degrees ran o,k for a couple of weeks. just a little pop out the exhaust reving in park.
ANSWER: Hi there:
with this much milage on the car it could be just about anything.. The basics you seemed to cover but I didn't see anything about spark plug wires. how about the spark plugs? ONLY USE AC Delco plugs and NOTHING ELSE and make sure they are gapped correctly. I would look for a possible vacuum leak with the engine running spary around the intake manifold with carb cleaner and see if the engine rpm's pick up if so you have a vacuuum leak. I would also make sure when it's hot you have enough fuel pressure. and it's steady and doesn't drop off when the engine rpm's are higher. That is where I would start looking.
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QUESTION: Good morning todd
thank for the respond, sorry about the last paragraph being doubled from question to u the other day. messed up on copy and paste.. anyway . wires only have 20k miles on them. and plugs have 10k .replaced them when ignition module went bad plus new coil. i replace distributer cap about ever 5k miles and have only use ac plugs cap at around .045.. been hearing a slight whistle sound for a month look for it never could pin in done. after responce from you ..check again found whistle sound . started to squeeze on map sensor unit. sound stop so i figure map sensor had a leak. bought new one . leak gone but car still runs same as discriped the other day . question i unplug electrical connector from unit but left vacuum hose attach. the problem of rough rev after hot in park is gone. it revs smooths. drove it around block ran smooth but lack some acceration. plug connector back in rough rev starts all back up again. need your opoining on that one because i dont under stand why.
spray everwere with carb cleaner , could'nt hear any differance except around idle air control. there might be some air leak aroung there. going to see if i can find o-ring for it. can i replace that ring with one like from a hardware store or does it take some kind of special one . pindle and housing inside are all nice and shining clean. and i ways clean the iac every couple years. please explain map sensor theory and best o-ring for it. the i go from there and see what happens..
ANSWER: U can use a o-ring from a hard ware store just as long as it fits and doesn't bind the valve up and it it sits flush against the throttle body. Like I mentioned before there could be any # of reasons your having an issue here. I would check the fuel pressure and see what you have there when you rev the engine up or drive it the pressure should remain steady and not drop off. another idea is a back pressure concern in the xhaust system if the catalitic converter is restricted the enegine will not breath properly drop the pipe at the exhaust manifild and drive it when it's hot and see what happens..
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QUESTION: HiTtodd
Thanks for the quick respouce. the catalitic converter has only 20k miles on it so it should be fine
and there is no shrader valve on fuel .might have to install one for last resort.cant really afford a
a new fuel pump and replace 20 year old straps to hold it back up right now..thanks for the info
on the o-ring. did figure 2 things out. i put 180 dergree thermostat instead of a 195 dregree that it
calls for by mistake. would 15 degrees make that bad of a diiference and and i think a lot of this
trouble started were the vacuum hose goes from the valve cover to the crankcase filter that attaches
to the air cleaner. the hose has always been lose or not a tight fit. so a month ago a put
heavy duty zip ties on both in's of the vacuum hose . before i could barley fill it suck any air through.
now it will suck my finger hard to it . like your hand over a shop vac hose. So i thing i made too
air tight and the motor found a new place to suck in air. and mess things up.. So i cut one end
of zip tie off the hose. and rev in park. problem feels and sounds 75 % better i,ll cut the other in when
the rain stops. and see what happens. sometimes u got to cheat it when u have do. Dont like to
but have no choice right now with the economy. Well if all else fails i cut in a shrader valve and check
pressure. Question is 13 to 17 lbs. of pressure at all times or 13 at idle and 17 under load..
I have a few question that need answered. now just a few other question to check....
1. will spark wires loose their resitance when hot? only 20k miles on them.spark plugs 10K
2. how to i ohm test the coil from the two plugs that plug in -4 prongs . what are the numbers
post to be hot and cold maybe coil breaking down when hot.
3. why under load, which i mean by driving, does run pretty good now from stop to 65 mph.
but in park while reving when motor hot it sounds rough out the exhaust?
4. The bucking and jerking is barely noticable now . how is that fuel pressure related when
worse reving in park than under load driving?
5. To u think replacing air temp sensor would help that much?
6. original fuel filter had 94K miles on it. this one only has 21k miles. Should it be replaced?
7. so having an air leak its really running richer reving in idle than leaner.
Well i think that just about covers it all. thank you for all your time and wisdom and know How!!!!
Thank you again and again Todd
Your Awsome
Steve
AnswerYou over thinking this problem.
put the correct size thermostat back in the car it will affect fuel economy. spark plugs resiatns will change with tempature every electronic part changes resistance with tempature. changing an air temp sensor I don't think will help you. what you really need here is a true scan tool not a code reader. a scan tool will allow you to look at what's going on here before you start throwing more parts ay this that it doesn't need. you need to see what the fule trim is at with it running at idle and also driving down the road. and it the trim is far off the correct #'s then look at a reaso nwhy the car is running rich or lean. as for the fuel pressure changine with more of a laod on the engien the pressure should rise slightly which it is that is normal. Some of the bug box car arts store have tool rentals and they may have scan tools that can be rented.
