Mechanics

HESITATES UNDER HARD ACCELERATION

1996 Dodge Avenger

Engine Performance problem
1996 Dodge Avenger 6 cyl Front Wheel Drive Automatic 159000 miles

Hello, I guess to start things off, I had just replaced the transmission on my 96 dodge avenger es, at 158000 miles. Car ran fine with no problems for 2 full days after tranny eplacement. I went about 15 miles to take car of something and on the way back I figured I would fill her up. Well for 10 more miles it still run smooth. I slowed down to make a turn in my driveway and it started to stall, missin like crazy. So I went to the parts store and got some new plugs, wires, cap, and rotor. Figuring it set for so long it could of used it anyways. So that didnt change anything. I then changed the fuel filter and put some dry gas in the tank figureing it had to be water in my tank. Well that didnt change anything either. Since doing this I have prolly out 30 gallons total in the tank and nothing changed. Well I had a map sensor code so I replaced it and I also replaced the TPS. Still nothing changed and still had map sensor code. So I thaught PCM or wiring issue. Look at wiring closely and got a different PCM. Well guess what. Nothing changed. So I got a can of sea foam and some new plugs and replaced the plugs and cleaned the intake all up really good. Also while I had it all apart I changed the gaskets for the upper and lower plenum. Well I atleast idols fine with hardly and miss or anything. I can drive it but it misses much more the hotter it gets. First startup I can drive it almost like nothings wrong. Anyways under medium to hard acceleration it misses like crazy. Anything over 3K rpm theres not hesitation and no miss as far as I can tell with that rpm anyways. Fuel injectors are fine and work correctly. If I start the car and floor it it sits at 1500 rpms just bogging away and will not jump up till I release the pedal. Could this be a fuel pump or a distributor problem. I have been told dis. But its 500+ dollars and I want a opinion from a pro. So thank you very much if you could help me out with this. Oh yea the only code I get now is 43 with the key on key off trick, which is mutiple cylinder misfire. Well I hope to here from someone soon. Thank you.
Avatar
Avengerweezel77
May 30, 2009.



Multiple missfire is common with faulty fuel pump what is the fuel pressure?

Docfixit
May 30, 2009.
I will have to rent the tool to check it but as soon as I get it Ill let you know thank you for a fast reply : )

Tiny
Avengerweezel77
May 30, 2009.
So I finally rigged this thing up so I could check the pressure without blowing myself up. Well It stayed at 51 at idle but when I hit the gas it dropped to 48 psi. Im not sure but I was told it should go up like 3-5 psi. Anyways I have a new regulator and filter so Im not sure if this drop is enough to say the pump is to blame. Let you know what you think plz. Thank you again

Tiny
Avengerweezel77
Oct 25, 2009.
Fuel pressure good 47-50 psi. Code 43 requires some specialized test equipment but can check out some basics-Compression test-Check spark is it blue/white with a snap?-Test Ignition Power Transistor see diagram, with battery applied should read continuity pwoer removed no continuity.


http://www.2carpros.com/forum/automotive_pictures/198357_Graphic_212.jpg


Docfixit
Oct 26, 2009.
Well ok thats one more thin down lol. Well it is sparking ok. But im not too sure if somehow it is affected when the trottle is pressed. The last part of your reply im not sure what you mean. Could you expain a little bit more plz? Im just hatin this mitubishi motor lately. Anyways thank you and I will have to see if I can rent the compression tool ty.

Tiny
Avengerweezel77
Oct 26, 2009.
Forgot illustration does this help?

Docfixit
Oct 26, 2009.
Well I have checked the conectors and cleaned them. But Im just wondering why I need to check continuity. I mean obviously its working up to par since its sparking and works fine with light throttle tension. Well one more thing im not sure of once I had it checked with a scanner one of my buddies brother had. One thing I remember is he said he dont know why at idle my TPS shows as 24-25% throttle I dont know but that sounds too high for me I thaught at highest it should read like 8-10%. As far as the compression check my only thing is why would it run perfect throughout rpm ranges if I had bad commpression. See if I slowly press the throttle it will redline without the slightest misfire. Only when I jam on it does it do what its doing. I just wish there was a way to put a video on here exactly what its doing cause its hard to explain. Anyways thank you again. Till next time.

Tiny
Avengerweezel77
Oct 30, 2009.
Well recently I put a new battery in it. But anyways it runs perfect other then the fact that I cant floor it. Im just wondering if it could be the alternator somehow thats all I got left to check. I made a video of what its doing I just dont know how or even if I can put it on here. The catalytic convertor is now off the car and I straight piped it so my neighbors dont come out shooting lol. So im ganna wait for a few more ideas but soon putting it the lawn with a free sign on it lol. Well thank you. Again.

Tiny
Avengerweezel77
Jan 3, 2010.
Could be coil breaking up under load as cylinder compression and heat rise takes more coil output to bridge plug gap. With light steady acceleration coil can keep up. Worth a shot

Docfixit
Jan 3, 2010.
Well thank you very much its one of very few (very very few) I have left to change. I will see what happens I mean I i have the extra cash right now so Ill just check it out. Thank you again and sorry it has been so long. Ill let you know if it works or not.

Tiny
Avengerweezel77
Feb 21, 2010.
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