Ok, Thanks you guys so much. i think i will attempt it with the intake on, and if not, ill pull it again. the iol pan does have to come off correct? to replace the lower front gasket? oh , ill read the link. thanks again. greg.

bogus, i had it apart last summer to replace injectors and a leaking intake gasket. didnt really want to do it again if the cam can be installed without pulling it.waiting on my service manuel so i can run the charts on my code 33. thanks for the link bogus.. and yes, iam talking about the lifter tool or magnets to hold the lifters up. will this work on this engine? what about the oil pump rod. it pulls straight up doesnt it? thanks guys..

flyboy,. i have a question sir about an old post if u dont mind. will the lifter tool that you sugested work on a l98 to change the cam without pulling the intake? it was posted that it would not work on the lt1-lt4 because of the oil pump drive shaft location. i think i read where you did it on the l98. thanks for the info..greg..

Ok but i did find something that seems odd. when i can make it screew up and run rough, while it is running, not very well i might add, i can unplug the vacumm line from the map completly, and has no change. now, when it is runing normally, if u unplug the map, it will die.. so... i think it is going back into open loop and running of of the preset values, when the ses light is on. iam thinkin ecm maybe? what do u think bogus.? thanks..

bogus, i have the egr vacuum hose disconected ans pluged off. but i did discover something tonight. when i was pulling into the garage it is slightly uphill and, when it was under slight throttle it was starting to cut out and miss. i worked the throttle body at idle, slightly reving up and down in netural and it would cut out and bogg down. it completely died a couple of times.. the good thing is, now i know how to make it act up. this is all with the ac on. there is a large vacumm line on the throttle body that goes to the canister i think. is it possible it is something to do with that? gettin closer maybe...Idea... throttle body.. at part trottle could it have a vacuum leak?

bogus, sometimes it will idle and run good with the ac on. drove it earler today with ac on, when engine cool everything is ok. when it gets to normal temp.. and, you slow down or come to a light, push the clutch in and then while idleing it will drop rpm, start to die, miss, and seems to run very rich. this all happens when the ses light comes on.. yes iam gone need more diagnostic equipment.acts like something is knocking the map completly out of the loop..i need a laptop or recorder i guess. not a normal problem for sure.. thanks again..greg.

Well its doing it again. every time i turn on the ac, it drops rpm, and cuts out acting like it wants do die, and it will.. if u turn the air off quick enough it will go back to running normal.. still throwing code 33..wish i had a back up ecm. man, this is a strange one...

bogus, it only happens when hot. yeah, ive never seen a ign module come ond go like this either. dont think it is the culprit.guess the only thing to do now is get recorder and drive around till it happens, then look at the data. problem is i live in the sticks, and most around here just give ya a funny look if you ask about one.lol.. next step is a factory servica manuel, that i need anyway.. thanks for all your help. this is a great site way better than any ive been on. keep up the good work bogus..greg..

Ok everything cks out good. ac circut is working properly. the engine stumbles with the ac already on and cooling.also, it happens only at slow speeds or idle.something is droping out. thats why i replaced the coil, cap, rotor, etc.one thing i haven replaced id the ign. module. would it through an ign. code of any kind? seems to me that when it starts to cut out, the vacuum drops off telling the map high voltage = no vacumm. correct?Idk.. this one is testing me.lol..thanks guys for all the sugestions.. ill keep diggin. greg..

Ok thanks flyboy. now its time to dig in.ill run the charts and post back.you fellas are great! thanks..greg..

Yes, i have. I also put the original AC Delco back on at one point with same results. I thought maybe it could be something vacumm related with ac blend doors or control unit, but everything works like its supposed to. Is it possible that the replacement and the original map sensors are bad? guess it could happen. ill ck some more things and post back. but my list is getting very short now.. thanks guys..

Jeffk, where do you find these? they are way cool!!

Yeah, Bogus i hope your right. i have replaced tha IAC and cleaned the TB. seems to me also that its something vacuum related, but cant figure out what. when it stumbles it almost feel like when you disconect the vacumm hose from the map sensor at idle. runs like crap. I like a challenge, but this is getting ridiculous!lol..Thanks

Thanks Bogas and to all.. yes, that is regulated pressure. seems to be in spec when unpluged..I have ckd the vacuum lines, and replaced all the suspect ones.i also did change the map sensor with same results.car seems to run perfect except for this glitch. have also replaced, cap, rotor, and put a high voltege coil on, along with accel 8mm plug wires and ngk plugs. all new..this car hates me, but iam not gona give up. running out of ideas.. thanks guys..greg.. Oh yes, it is a 6 speed..

Will do.. thank you..

First of all like to say howdy to all, and am a new member and this is my first post. I have a 90 conv. that has a code 33 Map voltege high that only occurs when the ac is on. the car will stumble and act like it wants to die right before light comes on, then goes off and run fine after that. have changed; map sensor, iac, tps, and egr all over the last year and still has this problem. vacuum at idle is 22 and with ac on is 19 or 20. iam at my end with this.could it be the ecm? thanks for letting me post..Oh forgot to mension, fuel injectors, bosh 3, new pump and regulator. fp is 34 to36 at idle. thanks..