Hi,

My car runs fine for about 30 minutes or so then starts running like ****. Barely has power, sounds awful -- I know i have an exhaust manifold leak, but would that be enough to make it run like this? No check engine light comes on. Anyone have any ideas?

 

If the car starts up great but then seems to loose power, you could be getting knocks, and the computer is retarding the timing to compensate. Try going to a higher octane and see if it makes a difference. Also, check your base timing. Too much advanced base timing will cause knock.

 

i'm not getting knocks -- it runs great, then gradually gets worse after 30 min or so of running -- no knocks jsut lack of power - could this be something to do with an oxygen sensor or air/fuel mixture ratio? the car is TBI - 89 TA

 

Are you saying you don't feel knocks, or that you hooked up to the ALDL and saw that the ECM is not picking up any knocks. I never felt knocks either, beacuse the knock sensor and ECM were doing their job. They retarded the timing before the engine knocked bad enough to notice. I hooked my laptop up to the ALDL, and sure enough the knock counter was way up within 15 minutes of driving, effectively retarded the timing advance and decreasing performance

 

I've not had the timing checked -- but no I"m not feeling any surges or knocks - dont' hear any knocks -- no rattles - -it just loses power after about 20 or 30 minutes of driving -- you kinda have to ease the gas to it so that it will pick up speed enough to get back to the house with it -

 

I'm by no means an expert but have you checked your fuel pressure with a fuel pressure guage.Unlike must my fuel pump went slowely over a period of a month or so.Exactly like you are discribing...Leave the house running great, get 15-20 minutes away and will barely move.I had to feather the gas all the way back.Too much pressure on gas pedal it would really bog/snort/caugh let almost all the way off gas and it would at least move 15-25mph.
Just a suggestion based on my experience.

 

hi,

yes i have a new fuel pump, new plugs and wires, new distributor -- so im not sure what it is -

 

test your coil

 

I had the EXACT same problem with my girlfriend's Corsica and it ended up being a plug wire was arching across the head right at the plug boot. I changed her plugs and wires and the problem was corrected. I don't know why it would run fine for a little while and then mess up but it did. I know you said that you have new plugs, wires, and cap but weirder things happen. You could just have a bad plug wire or even a cracked cap. Find a dark area and look real closely around the boots going to the plugs and even to the cap and then check the area around the cap as well. Listen for a faint ticking sound. I looked for a good 10-15 minutes before I finally saw where hers was arching.

 

i just recently took care of a similar problem with mine. start off cold, had plenty of power, good acceleration. after it got good and warm, it would buck,kick, die at stop light, no power.....thought it was the ignition module. new ac delco module and didn't fix the problem.disconnected msd ignition, still didn't help. turned out it was the coil. i happened to have a junk yard one in my car at the time. swapped them out and voila...ran like a champ again!

 

I have the same problem now, but got a brand new dizzy,ignition coil,ignition module,cap and rotor. It ran fine for about a week, and now I get a O2 sensor code and an EST code, I have not been able to figure this out. I changed the O2 sensor and The ignition module is brand new(it came with the new distributor). I m ready to shoot the car

 

A brand new ignition module doesn't mean squat. Those can be bad out of the box. I went to a parts store to pick one up for my TA and I always have them test the ignition module on their machine before I buy it. Well, they had 3 modules for my car in stock (all same brand) and every one of them tested bad right out of the box.

 

Ill try the module, Thanks for the info

 

I try to crank the car in the AM and it won't start. I thought it was the key, so i used my brand new key and still wouldnt work -- in the afternoon when i get off work it will start right up with either key -- but im still having the running rough issue after it is running for 20 or 30 minutes - I've not had anything checked yet -- but could this be the distributer having moisture in it from the morning -- the car is in a closed garage???

 

I would check the resistance on the pick up coil. Not sure the exact numbers, but if you have the Hayes or Chilton book It ll tell you the exact number that you need. Also you can try a NEW ignition module. I had in the past test them in the auto parts with their bench, and it does not get as near as the temp that your car does.

 

Now the damn thing won't start at all!! Whats up???

 

Man, Im almost positive is your pick up coil. Assuming that you have fuel. That is the same thing that happend to me about a month ago. I just went and bought a new distributor, since my old one was coming apart and was corroded.

 

where is this located? I have a new distributor that I've never used -- how hard is it to install?

 

Well before you take the distrubutor, check the resistance on the pick up coil. Take the distributor cap off. You will see the ignition module sort of facing the firewall. It has 3 connectors. 2 of them face the firewall, the other one is the one you are looking for. It has a green and white wires if I remember correctly. That is the connector that you need to check the resistance on. The pick up coil is located underneath of the distributor rotor. And if it is bad, the whole dizzy needs to come off. The part is not expensive, probably around $20 bucks or so. Do a search on the forum to check the correct resistance on the coil. If I remember it should be around 400 ohms. If you dont get resistance than your pick up coil is bad. Now,I DO NOT REMEMBER CORRECTLY ON THE NUMBERS.

 

Well before you take the distrubutor, check the resistance on the pick up coil. Take the distributor cap off. You will see the ignition module sort of facing the firewall. It has 3 connectors. 2 of them face the firewall, the other one is the one you are looking for. It has a green and white wires if I remember correctly. That is the connector that you need to check the resistance on. The pick up coil is located underneath of the distributor rotor. And if it is bad, the whole dizzy needs to come off. The part is not expensive, probably around $20 bucks or so. Do a search on the forum to check the correct resistance on the coil. If I remember it should be around 400 ohms. If you dont get resistance than your pick up coil is bad. Now,I DO NOT REMEMBER CORRECTLY ON THE NUMBERS. So if you have the manual for the car it ll help you on this. Hope this can help you, since Im learning as I go along too.